Barcelona would not be Barcelona without the work of two titans of the Modernista movement—Lluís Domènech i Montaner and the more famous Antoni Gaudí. From the Hospital Sant Pau to the Sagrada Familia, their colorful, nature-inspired, trippy works of art continue to enchant.

While Montaner was certainly a master, it was Gaudí’s work that made the Modernista movement world-renowned. His buildings made the phrase “attention to detail” seem like an understatement. At Palau Guell, for instance, he seamlessly blended masterworks of iron, wood, glass, and tile into a private home, the likes of which the world had never seen. His Barcelona masterpiece, Sagrada Familia, which is still under construction, is mind-numbing in large part because it’s hard to fathom how a building so awe-inspiring in size can be simultaneously unforgettable for its minute details. Sadly, his life ended in tragedy in 1926, as he was struck at age 73 by a tram, and because of his clothing (Gaudí dressed in clothes often described as rags) he did not receive immediate care and died.

Then, in 1936 during the Spanish Civil War, his studio and his papers were destroyed in a fire. However, in 1956 his former assistant put together a monograph showing that the Catalan master had once hoped to bring some of his architectural sparkle to New York City’s skyline with a futuristic curved tower that would have been the tallest in the world.

Joan Matamala Flotats was a sculptor whose father, Lorenzo Matamala y Pinyol had been the main model-maker and sculptor for the Sagrada Familia. In 1956 Matamala the son published a 64-page monograph titled “Cuando el Nuevo Continente llamaba a Gaudí (When the New World called Gaudí) (1908-1911).” The monograph revealed for the first time a proposal for a monumental hotel tower in Manhattan.

In May 1908, the story goes, two U.S. businessmen visited Gaudí in Barcelona to convince him to design a hotel for New York City. One of the businessmen was supposedly the president of the New York and New Jersey Railroad Company (and future Treasury secretary), William Gibbs McAdoo.

The building that Gaudí proposed was unlike anything New York’s cast-iron Beaux-Arts skyline had seen.

Dubbed the Hotel Attraction (according to Matamala’s recollection), Gaudí proposed a parabolic skyscraper towering over the city at 360 meters. It would have been the tallest building in the world until the completion of the Empire State Building. The central parabolic tower would be surrounded by domed towers merged into its side giving it what I can only describe as a very tall version of Dugtrio from Pokémon.

There would have been rooms in the domed towers and restaurants in the central tower. The top of the tower would feature a room clocking in at roughly 400 feet tall, which would have featured a 30-foot copy of the Statue of Liberty. On the outside on top of this hall, a giant star, dubbed a “sphere of all space” by Matamala, would have allowed views of Manhattan for 30 tourists at a time. The restaurant level was made up by the conjoined towers clocking in at 50-feet high and were meant to represent five of the continents and could each seat 400. The whole tower would have been clad in kaleidoscopic colors of marble and polychrome tile.

The exact location for the proposed tower is unknown, but a group of architects and historians argued that it was intended for the site of the first World Trade Center towers and put it forward for the Ground Zero memorial design competition in 2003. Needless to say, it was not chosen.

As befits a mysterious project like this, there are a number of theories as to why the hotel was never built. Some believe it was the budget that would have been required, or that it was the amount of time (an estimated eight years) it would have taken to complete. Others with a greater flair for the dramatic argue that it was canceled because Gaudí fell sick, or that his political leanings meant he did not like that the hotel was for the wealthy.

In 1971, the monograph was bought by Professor Juan Bassegoda i Nonell, the now deceased former curator of the Real Catedra Gaudí at the University of Barcelona. Included in the monograph were multiple sketches of the plans attributed to Gaudí. Matamala, who would have been a teenager toiling away in Gaudí’s studio at the time of the plan, also made ten drawings of his own based on his memory of what Gaudí was working on. Bassegoda told the New York Times in 2003 that ''for 40 years I have been studying Gaudí's works, and I am sure the drawings are authentic.’' While various architectural historians knew about the project (Clovis Prevost and Robert Descharnes had written about it in their 1969 book about Gaudí), the full extent of the monograph wasn’t revealed to the public until 1989 when Bassegoda published it.

When Gaudí graduated from architecture school, its director famously declared: “I do not know if we have awarded this degree to a madman or to a genius; only time will tell.” More than a century removed from his death, Gaudí’s plans for Manhattan are a reminder that the two aren’t mutually exclusive.

This is part of our weekly series, Lost Masterpieces, about the greatest buildings and works of art that were destroyed or never completed.