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