Uber is considering a massive lease in Chicago’s long-vacant Old Post Office at 433 West Van Buren Street, according to news reports.

The tech company is looking at 450,000 square feet in the 2.8-million-square-foot redevelopment which could bring thousands of employees to the city, the Chicago Tribune confirmed first.

The first tenant to sign a lease at the building was Walgreens in 2018. The company committed to 200,000 square feet and plans to bring 1,800 employees in the fall. Five other companies have signed much smaller leases including Ferrara Candy, the Chicago Metropolitan Agency, ad agency AbelsonTaylor, and two Kroger companies.

New York-based 601W Companies is working on the $800 million-plus renovation of the landmark building. In 2017, architecture firm Gensler released renderings of the project which includes a landscaped riverfront promenade with a water taxi stop.

Much of the Art Deco building will be restored, including the cavernous lobby’s gray limestone and black granite. The building, which was empty for decades, needed an extensive rehabilitation and 2,400 new windows.

Designed by Graham, Anderson, Probst & White, the 12-story Post Office was built in phases from 1921 to 1932. It served as the central point for the U.S. mail system until 1996 when the agency moved to another building nearby.

Today we welcomed @Walgreens to its new home at Chicago's Old Post Office! Approx 1,800 employees will work in the 200K-sq-ft office when it is fully open next year. This will be the largest number of corporate employees Walgreens has ever had in Chicago. https://t.co/3y1pEoTfiI pic.twitter.com/2KQUCu7LQa — Mayor Rahm Emanuel (@ChicagosMayor) June 18, 2018