In 1991, construction workers here uncovered over 400 stacked wooden caskets, just 16ft to 28ft below street level. The boxes contained the remains of enslaved Africans (nearby Trinity Church graveyard had banned the burial of Africans at the time). Today, a memorial and visitors center honors an estimated 15,000 Africans buried here during the 17th and 18th centuries.

The site is permanently protected as a National Historic Landmark, and today it’s part of the National Parks Service. The visitors center requires airportlike security screenings, so leave your nail files in the hotel.