This excellent photo was staring me in the face from my Long Island historic wall calendar last month. Google Image Search helped me find more information about it.
Steiner Street, approaching Washington. Google Street View shows one of the buildings in the background of the photo as still standing. More info at reddit.com
His name was Ota Benga. Radio Diaries interviews an old woman who was his friend when she was a very little girl.
Even at the time, the exhibit was controversial, protested by African-American leaders.
The Man in the Zoo [Radio Diaries]