On the National Mall — within sight of the Capitol dome — stood a three-story yellow brick building that became one of the most feared addresses in America. Known as the Yellow House, this slave pen and auction depot was operated first by James Robey and later by William H. Williams, two of the most prolific domestic slave traders in the country. Enslaved men, women, and children were held in its high-walled yard before being sold and transported south to the cotton and sugar fields of the Deep South. Testimonies from survivors, including abolitionist Solomon Northup, described the conditions as deliberately dehumanizing — a processing facility for human beings made to profit off their terror. The site stood until the Compromise of 1850 prohibited the slave trade in the District of Columbia, but by then tens of thousands of lives had passed through its gates.