Do slave houses still exists

In many place is the US there are carefully maintained slave quarters at historical sites. Some examples of those are The Royall House and Slave Quarters in Medford MA, Aiken House in Charleston SC, and Evergreen Plantation in New Orleans LA, see photo linked below.

There are also a few remaining structures along the west coast of Africa where slaves were held awaiting ships to the new world. See the link below to Bunce Island in Sierra Leone.