Home of Romans and later Capital of Italy.
Withstood siege only once in the 6th century when the city was held by the Byzantine army led by Belisarius. This was the only time Rome withstood siege... mainly cause Roman politicians were wusses. Funny that!
Wasn't built in a day but was burnt down several times in 24 hours.
Current home the the Pope and as such no doubt a major target for the extremist Muslim hordes (... like anywhere isn't these days!)
Also a rather fruity series made by HBO and shown on the BBC. Much fighting & shagging from Roman squaddies.
HBO Rome website