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The clock tower and observation deck at the Old Post Office on Pennsylvania Avenue will close next week for two years as Donald Trump‘s organization begins its renovation of the 1889 building into a $200 million luxury hotel.

At 315 feet, the clock tower is the third-tallest structure in the District. Its observation deck, 270 feet off the ground, gives visitors views of the city from well above the Height Act–imposed limit on most building heights.

The Trump Organization plans to begin construction in June, and federal tenants will move out of the building by May 31. In preparation for the construction, the clock tower will close on May 1. The National Park Service, which runs the tourist attraction, expects the tower to reopen in spring 2016.

“Ongoing renovation work to convert the 115 year old Old Post Office building into a hotel will prevent safe visitor access and require closing the tower and observation deck to the public for approximately 2 years,” the Park Service announced on its website.

What would Back to the Future say?

Photo from the National Park Service