A ziggurat was a pyramid-like structure.
The ziggurat of Zababa was the largest temple in Kish. Uruk also had a ziggurat. Gilgamesh thought that Qataka's escape pod was a ziggurat. (PROSE: Timewyrm: Genesys)
The Millennium Hall in London was a ziggurat. (PROSE: Millennial Rites)
The Unthinkable City had a ziggurat in its centre. (PROSE: Alien Bodies)
The Yemayan temple on Yemaya 4 was a ziggurat. (PROSE: Sleepy)
Bev Tarrant investigated what appeared to be a ziggurat on Kar-Charrat, but was actually a Dalek hibernation unit. (AUDIO: The Genocide Machine)
PROTEC's headquarters was a massive glass ziggurat in Hades, the capital city of Pluto. (PROSE: Weapons Grade Snake Oil)
The Doctor's TARDIS had a ziggurat. (PROSE: Sky Pirates!)