[PzLdr]

Wasn't the Coliseum built over part of Nero's palace [the artificial lake , as well well as some of the filled in structure]?

[NormsRevenge]

Not sure, sounds like it may have,, ran across this map..

from http://www.romeguide.it/domus_aureaeng/domus_aurea.htm

http://www.the-colosseum.net/history/domusaurea.htm