Santiago Calatrava

“I have to say, this is much more than a station, isn’t it?” Santiago Calatrava told a reporter when the Oculus, the main hall of the new World Trade Center’s transit hub, opened in 2016. The charismatic Spanish-born architect is known for his curvy, neo-futurist projects—and his soaring budgets. The Oculus ended up costing twice its original $2.2 billion budget, even more than the 1,776-foot-tall One World Trade Center across the plaza, and took more than a decade to finish.

Calatrava, who had studied drawing and painting before taking up architecture, first pitched his concept at a public forum in January 2004. After sketching a picture of a child releasing a bird, he demonstrated to a rapt audience how the building’s roof—a pair of enormous hydraulic “wings”—would open and close. “On a beautiful summer day, the building can work not as a greenhouse but as an open space.” He got a standing ovation.

The hydraulic wings proved to be an engineering impossibility, but a full-length retractable skylight, composed of 224 panes of glass, allowed Calatrava to finally realize Daniel Libeskind’s notional “wedge of light.” Every September 11th at 10:28 A.M.—the moment the second tower fell—a 365-foot-long ray of sunlight, weather-permitting, spans the entire length of the concourse, reflecting off the white Italian-marble floors.