Overbrook is one of the few zones that owes its destruction to a traditional supervillain, rather than to the Rikti War. The supervillain is the one who eventually gave the zone its new name: Faultline. A fairly normal plot, Faultline had installed earthquake generating bombs around Overbrook, which he would detonate unless the city paid him a ransom. A team of younger heroes went in to stop him, and unfortunately, they failed. The zone was completely cracked apart with jutting angles and deep crevices.
Also of note is the Paragon City Reservoir at the south end of the zone. This reservoir still provides much of the citys fresh water supply, but the destruction of Overbrook makes it more vulnerable than ever. However, most of the villains in the zone don't seem to have much purpose for being there other than the lack of police and hero presence (although scrap metal always draws the Clockwork).