The Kaled Dome was the home city of the Kaled race on Skaro, with the Thals, their enemies, living in the Thal Dome across the wastelands. The dome held thousands of Kaleds.
Buried underneath the dome was a bunker, the location of Davros and the Kaled Scientific Elite for most of their time. When the Thals launched their missile, the bunker remained unharmed but the entire Kaled dome was destroyed. (DW: Genesis of the Daleks)
It is possible that the Daleks later rebuilt the Dome into the Dalek City. Even if, in the original timeline before the Time Lords intervened, the Dome had never been destroyed, it may still have become the Dalek City.