Opened in 2004, the center also pays tribute to all efforts to "abolish human enslavement and secure freedom for all people".

Many found refuge in the city, some staying there temporarily before heading north to gain freedom in Canada.

The exterior features rough travertine stone from Tivoli, Italy on the east and west faces of the building, and copper panels on the north and south.

According to Walter Blackburn, one of its primary architects before his death, the building's "undulating quality" expresses the fields and the river that escaping slaves crossed to reach freedom.

First Lady Laura Bush, Oprah Winfrey, and Muhammad Ali attended the groundbreaking ceremony on June 17, 2002.

The pen was originally owned by Captain John Anderson, a veteran of the Revolutionary War and slave trader.

On the second floor are a row of wrought iron rings (see photo at right) through which a central chain ran, tethering men on either side.