Internet History Sourcebooks Project
Fordham University: Byzantine Studies: Constantinople, Queen of Cities
Click here for a list of maps & photos depicting the Theodosian walls, the Hippodrome, Hagia Sophia, and modern Istanbul. Site by Fordham University.
Princeton University
Model of the Hagia Sophia
This page contains a description of the Hagia Sophia along with pictures & a computer drafted model of the structure.
Other
Times: Recreation at the Crossroads of the World
Good site for historical overview of the rise and fall of the New York Hippodrome. Also mentions a one of its early productions, "A Yankee Circus on Mars".