A Ziggurat is a type of monumental building, a temple which takes the form of a stepped pyramid.
Ziggurat's were amongst the buildings built by the Rajathan culture on Rajatha Prime. Rajathan ziggurat's were tall structures featuring steep walls and steep flights of steps, they were largely adorned with symbolic markings. The upper levels of Rajathan ziggurat's featured ceremonial entrances to Heaven and the Underworld. (TNG comic: Captain's Pleasure)