Leonardo Torres Quevedo (Spanish: [leoˈnaɾðo ˈtores keˈβeðo]; 28 December 1852 – 18 December 1936) was a Spanish civil engineer, mathematician, and inventor known for his many engineering innovations, including aerial trams, airships, catamarans, and remote control systems. He was also a pioneer in computing and robotics. Torres was a member of several scientific and cultural institutions and held important positions, such as a member of the Real Academia Española from 1920 to 1936 and president of the Spanish Royal Academy of Sciences from 1928 to 1934. In 1927, he became a foreign associate of the French Academy of Sciences.

His first major invention was a cable car system patented in 1887 for safely transporting people. This work led to the opening of the Whirlpool Aero Car in Niagara Falls in 1916. In the 1890s, Torres focused on analog computation. He published technical studies, Sur les machines algébriques (1895) and Machines à calculer (1901), which earned him recognition in France for building machines that solved real and complex roots of polynomials. He made important contributions to aeronautics in the early 20th century, inventing the non-rigid Astra-Torres airships, a trilobed structure that helped British and French armies during World War I. His work in airship engineering also led to advancements in radio control systems between 1901 and 1905 with the Telekine, which introduced modern principles for wireless remote control.

From his Laboratory of Automation, established in 1907, Torres created one of his greatest inventions: El Ajedrecista (The Chess Player) in 1912. This electromagnetic device could play a limited form of chess, showing that machines could follow specific rules (heuristics) and represented a major achievement in automatics and control theory. In 1914, he wrote Essays on Automatics, where he discussed thinking machines and designed a special-purpose electromechanical calculator, introducing ideas like floating-point arithmetic that remain relevant today. British historian Brian Randell called this work "a fascinating piece worth reading even today." Later, in 1920, Torres demonstrated a working typewriter-controlled calculating machine, proving the feasibility of an electromechanical analytical engine.

Before retiring in 1930, Torres designed other notable projects, including the Buque campamento (Camp-Vessel, 1913), a balloon carrier for airships, and the Binave (Twin Ship, 1916), a multihull steel ship powered by two propellers. In addition to his engineering work, Torres was active in literature and supported the Esperanto language.

Early life and education

Torres was born on December 28, 1852, on the Feast of the Holy Innocents, in Santa Cruz de Iguña, Cantabria, Spain. His father, Luis Torres Vildósola y Urquijo (1818–1891), was a civil engineer in Bilbao, where he worked as a railway engineer. His mother was Valentina Quevedo de la Maza (1825–1891). He had two siblings: Joaquina, born in 1851, and Luis, born in 1855. The family mostly lived in Bilbao, but they also spent long periods in his mother’s family home in the mountain region of Cantabria. As a child, he often lived apart from his parents because of their work trips. He was cared for by the Barrenechea sisters, relatives on his father’s side, who named him their heir, which helped him become independent later in life.

He studied high school in Bilbao and later went to Paris to attend the college of the Christian Brothers, where he studied for two years (1868 and 1869). There, he learned about French culture, customs, and language, which helped him in his future work with scientists and technical institutions. In 1870, his father was transferred, and the family moved to Madrid. The next year, Torres began his higher education at the Official School of the Road Engineers’ Corps. In 1873, he temporarily stopped his studies to volunteer with his brother Luis to defend Bilbao, which had been surrounded by Carlist troops during the Third Carlist War. After the siege of Bilbao ended in 1874, he returned to Madrid and finished his studies in 1876, graduating fourth in his class.

Career

Torres worked as a civil engineer for a few months on railway projects, just like his father. However, his curiosity and desire to learn led him to leave the Corps and focus on his own ideas. As a young entrepreneur who inherited a large family fortune, he traveled across Europe in 1877, visiting Italy, France, and Switzerland to study scientific and technical advances, especially in the early field of electricity. After returning to Spain, he settled in Santander, where he continued his independent research.

Torres began experimenting with cableways and cable cars early in his life, starting in his hometown of Molledo. In 1885, he built the first cableway to cross a depression about 40 meters (130 feet) deep. The cableway was 200 meters (660 feet) long and carried one person sitting in a chair attached to a cable. Another cable helped move the chair, and the engine was a pair of cows. Later, in 1887, he built a larger, motorized cableway over the Río León in Valle de Iguña, but this one was only for moving materials, not people.

These experiments led to his first patent on September 17, 1887, in Spain, titled "A multi-wire suspended aerial system." This design allowed for safe transportation of people, not just cargo. The patent was later extended to other countries, including the United States, Austria, Germany, France, the United Kingdom, and Italy. His cable car used a new system with multiple cables. One end of each cable was attached to fixed weights, and the other end was connected to moving weights through pulleys. This setup kept the tension in the cables constant, regardless of the load. The cables could bend more with heavier loads, but their safety remained predictable. This design was strong and safe, even if one support cable failed.

In April 1889, Torres presented his cableway in Switzerland, a country interested in such systems because of its mountainous geography. The cableway connected Pilatus-Kulm and Pilatus-Klimsenhorn on Mount Pilatus, spanning 2 kilometers with a steep gradient of 300 meters. In 1890, he returned to Switzerland to promote the project but failed to convince local authorities, who doubted the work of a Spanish engineer. Newspapers even published jokes and drawings about his plan. This failure, called the "Swiss failure," caused Torres to shift focus to other fields for several years.

In 1907, Torres successfully launched a public cableway in San Sebastián, called the Mount Ulia aerial ropeway. The journey was 280 meters long, with a drop of 28 meters, and took about three minutes. Each gondola could carry up to 18 people. The project was managed by the Society of Engineering Studies and Works of Bilbao, founded in 1906 by Valentín Gorbeña Ayarragaray, one of Torres' close friends. The Ulia cable car operated until 1917.

Torres' success inspired him to design the Spanish Aerocar, based on an idea by J. Enoch Thompson at Niagara Falls, Canada. The cableway stretched 550 meters across the whirlpool in the Niagara Gorge. It traveled at 7.2 kilometers per hour (4.5 miles per hour) and carried 35 passengers per trip. Each cable could support 9 tonnes (9.9 short tons) with a safety factor of 4.6. The project was built between 1914 and 1916 by the Niagara Spanish Aerocar Company Limited, using $110,000 (about $3.5 million in 2025) in capital. Torres' son, Gonzalo Torres Polanco, oversaw construction. The cableway opened to the public in 1916 and continues to operate today with no major accidents.

The Aero Car is the only remaining example of Torres' design for an aerial ferry. Though built in Canada, it was a Spanish project: designed by a Spaniard and constructed by a Spanish company with Spanish funding. In 1991, the Niagara Parks Commission honored Torres with the Leonardo Torres Quevedo Award, recognizing efforts to preserve his design. A plaque near the Aero Car Gift Shop notes it as an "International Historic Civil Engineering Site" and honors Torres' contributions.

Since the mid-19th century, devices like integrators and multipliers were known. Torres' work in this area began in 1893 with a paper titled "Memory about algebraic machines," presented to the Spanish Royal Academy of Sciences in Madrid. The paper was reviewed by Eduardo Saavedra in 1894 and published in a journal. Saavedra praised Torres' calculating machine as a significant achievement in Spanish science and recommended funding for the project.

In 1895, Torres presented "Sur les machines algébriques" with a model at the Bordeaux Congress and in Paris. In 1900, he shared a detailed work, "Calculating machines," with the Paris Academy of Sciences. A commission led by Marcel Deprez, Henri Poincaré, and Paul Appell supported the publication, noting that Torres' work provided a complete solution for building machines to solve algebraic and transcendental equations. His studies explored how mathematical formulas could be implemented mechanically, using continuous quantities and logarithmic scales.

Distinctions

Over the years, Torres received more decorations, prizes, and memberships in organizations. These included groups in Spain and other countries. In 1901, Torres joined the Spanish Royal Academy of Sciences in Madrid because of his work on algebraic machines. He later became president of the academy from 1928 to 1934. In 1916, King Alfonso XIII of Spain gave Torres the Echegaray Medal. In 1918, Torres refused to take the job of Minister of Development. In 1920, he was admitted to the Real Academia Española to fill the seat left empty by the death of Benito Pérez Galdós. In his speech, he spoke in a humble and humorous way.

That same year, Torres was elected president of the Spanish Royal Physics Society and the Royal Spanish Mathematical Society. He held this position until 1924. He also became a Corresponding Member of the French Academy of Sciences in the Mechanics Section. In 1921, he was appointed president of the International Spanish-American Union of Scientific Bibliography and Technology. From 1921 to 1928, he led the Spanish section of the International Committee for Weights and Measures. Because of his experience with instruments, he helped improve measurements in the laboratories of the International Bureau of Weights and Measures (BIPM). In 1923, he became an Honorary Academician of the Geneva Society of Physics and Natural History. In 1925, he was promoted to Corresponding Member of the Hispanic Society of America. In 1926, he became Honorary Inspector General of the Corps of Civil Engineers. On June 27, 1927, Torres was named one of the twelve foreign associate academicians of the French Academy of Sciences. He received 34 votes for this honor, more than Ernest Rutherford (4 votes) and Santiago Ramón y Cajal (2 votes).

His honors also include:
• Grand Cross of the Civil Order of Alfonso XII in 1906
• Parville Prize of the French Academy of Sciences in 1916
• Grand Cross of the Order of Charles III in 1921
• Grand Cross of the Military Order of Saint James of the Sword in 1921
• Commander of the Legion of Honour in 1922
• Honorary doctorate from the University of Paris in 1923
• Honorary doctorate from the University of Coimbra in 1925
• Grand-Cross Band of the Order of the Spanish Republic in 1934

Personal life, religious beliefs and death

On April 16, 1885, Torres married Luz Polanco y Navarro (1856–1954) in Portolín (Molledo). Their marriage lasted 51 years and resulted in eight children: three sons and five daughters. Their children were Leonardo (born 1887, died at age 2 in 1889), Gonzalo (born 1893, died in 1965; he became an engineer and worked as his father’s assistant), Luz, Valentina, Luisa, Julia (who died young), Joaquina, and Fernando. After the death of his first son in 1889, Torres moved his family to Madrid with the goal of carrying out the projects he had planned earlier. During this time, he attended the Athenæum in Madrid and participated in literary events at the Café Suizo, though he generally avoided political discussions. He lived for many years at number 3 on Calle de Válgame Dios.

Torres was a devout Catholic who often read the catechism and received communion every First Friday of the month. He read the catechism as if preparing himself for the peaceful end he believed was coming. His daughter Valentina once told him, “Dad, maybe you don’t fully understand the mysteries of faith, just as I don’t understand your inventions.” He responded, “Oh daughter, it’s just that from God to me there is an infinite distance.” When the Spanish Civil War began, his daughter Luz was arrested by the militia. To save her life, the family used the fact that Torres was a Commander of the Legion of Honour, with the help of the French Embassy. In his final moments, his family arranged for the sacraments to be administered to him despite challenges caused by religious persecution. As he received the extreme unction, he said his last words: “Memento homnia, quia pulvis eris et in pulverem reverteris” (“Remember, man, you are dust and to dust you will return”). On December 18, 1936, Torres died at his son Gonzalo’s home in Madrid during the Civil War, ten days before his eighty-fourth birthday. He was first buried in the Cementerio de la Almudena and later moved in 1957 to the monumental Saint Isidore Cemetery.

Legacy

During the difficult times of Spain’s Civil War, Torres’ death in 1936 received little attention. However, in 1937–38, newspapers like The New York Times and French mathematician Maurice d’Ocagne reported his death through obituaries and articles. D’Ocagne also gave lectures about Torres’ research in Paris and Brussels.

After his death, Torres was not forgotten. In 1939, the Spanish National Research Council (CSIC) was created. Architect Ricardo Fernández Vallespín was chosen to design and build a large building in Madrid to house the new Institute “Leonardo Torres Quevedo” of Applied Physics. The building was completed in 1943 and focused on designing tools, solving mechanical, electrical, and electronic problems. It became the foundation of the current Institute of Physical and Information Technologies “Leonardo Torres Quevedo” (ITEFI).

In 1940, Torres’ name was chosen by American philanthropist Archer Milton Huntington to be included on the building of the Hispanic Society of America.

In 1953, events to celebrate the 100th anniversary of Torres’ birth were held at the Spanish Royal Academy of Sciences. Scholars from Spain and other countries, including Louis Couffignal, Charles Lambert Manneback, and Aldo Ghizzetti, attended.

Two postage stamps were issued in Spain to honor Torres in 1955 and 1983. The 1983 stamp was printed alongside an image of the Niagara cable car, considered a work of genius.

In 1965, Madrid’s City Council placed a commemorative plaque on the building where Torres lived at Válgame Dios, 3, to inform residents that “the scientist who brought glory to Spain lived there.”

In 1978, Madrid honored Torres’ work at the Palacio de Cristal del Retiro. The event was organized by the College of Civil Engineers, led by José Antonio Fernández Ordóñez.

In 1982, the Leonardo Torres Quevedo National Research Award was created in Spain by the Ministry of Science to recognize Spanish scientists in engineering. The same year, the Leonardo Torres Quevedo Foundation (FLTQ) was established as a non-profit organization to promote research at the University of Cantabria and train professionals. The foundation’s headquarters was located at the University of Cantabria’s School of Civil Engineering.

In 1986, a bronze statue on a stone pedestal was built to mark the 50th anniversary of Torres’ death. The statue, created by sculptor Ramón Muriedas, was placed in Santa Cruz de Iguña, Torres’ birthplace.

Between the late 1980s and mid-1990s, three symposiums were held in Spain to discuss Torres’ life and work. These were titled Leonardo Torres Quevedo, su vida, su tiempo, su obra and took place in Molledo (1987), Camargo (1991), and Pozuelo de Alarcón (1995).

On July 19, 2008, Spain’s National Lottery honored the 100th anniversary of the Torres Quevedo airship built in Guadalajara, which marked the beginning of the Spanish Air Force. In November, the Leonardo Torres Quevedo Centre was opened in Santa Cruz, Molledo, to celebrate his life and work.

On December 28, 2012, Google honored Torres’ 160th birthday with a Google Doodle. The company also celebrated the 100th anniversary of El Ajedrecista, a device considered a marvel of its time and the “grandfather” of modern video games. A conference was held in November 2012 at the Technical University of Madrid to display Torres’ inventions.

Since 2015, an image of Torres’ Mount Ulia aerial ropeway, a cable car built in San Sebastián in 1907, has appeared on the visa page of Spanish passports.

On August 8, 2016, the 100th anniversary of the Whirlpool Aero Car’s uninterrupted operation was celebrated. The event included members of the Torres Quevedo family and the Spanish Ambassador to Canada, Carlos Gómez-Múgica. Niagara Parks Commission Chair Janice Thomson stated that the ceremony honored Torres’ contributions to engineering and tourism in Niagara.

In February 2022, a new turbosail named La Naumon was unveiled in Santander. The device was named after Torres. A museum called El Valle de los Inventos opened in La Serna de Iguña, offering exhibits, guided tours, and workshops about Torres’ inventions. On July 4, 2022, Iberia’s fifth Airbus A320neo for the year was named “Leonardo Torres Quevedo” in his honor.

On May 5, 2023, the Instituto Cervantes opened the Caja de las Letras to preserve Torres’ legacy. Items included in the collection are letters, manuscripts, books, postcards, and a schedule for the Niagara Falls cable car he designed. The collection also includes a milestone award from the Institute of Electrical and Electronics Engineers recognizing Torres’ invention of remote control with the Telekino in 1901. Torres’ granddaughter, Mercedes Torres Quevedo, thanked the Instituto Cervantes on behalf of her family for preserving her grandfather’s legacy. The collection is stored in box number 1275, with keys held by the institution and Torres’ descendants.

In fiction

Leonardo Torres Quevedo is one of the main characters in the novel Los horrores del escalpelo (The Horrors of the Scalpel, 2011), written by Daniel Mares. The story follows the Spanish engineer as he travels to London in 1888 to search for Maelzel's Chess Player, a mechanical machine believed to have been lost for many years. He teams up with Raimundo Aguirre, a thief and killer, who says he has a clue about the missing machine. Together, they search through London's underground and Victorian society. Their search is interrupted when the streets of the Whitechapel neighborhood are filled with the bodies of women who worked as prostitutes, which leads Torres and Aguirre to become involved in the search for Jack the Ripper.

Selected works

• "New aerial funicular railway system with multiple cables," Invention presentation. Switzerland (1889)
• "On algebraic machines," Proceedings of the Academy of Sciences (1895)
• "Calculating machines," Papers presented by various scholars to the Academy of Sciences of the French National Institute (1901)
• "A Preliminary Plan for a Steerable Balloon," The Aerophile (1902)
• "On telekinesis," Proceedings of the Academy of Sciences (1903)
• "On a system of notations and symbols intended to facilitate the description of machines," Public Works Journal (1907)
• "Essays on Automation. Its Definition. Theoretical Scope of Its Applications," General Review of Pure and Applied Sciences (1915)
• "Electromechanical Arithmometer," Bulletin of the Society for Encouraging National Industry (1920)