The Pau Sinkhole represented a naturally occurring geological formation that stretched far below the surface of the planet Utapau. Within this sinkhole was the subterranean habitat of Pau City, which was home to a million residents, including both Pau'ans and Utai.
The location of the Pau Sinkhole, along with the majority of Utapauan settlements, was on the planet's only continent, which was considered the most stable of the world's tectonic plates. Pau City was built as a vertical refuge within the sinkhole, primarily within underground caves. Access points to the outside and docking stations for starships were positioned along the inner walls of the cliff face. The sinkhole provided protection for the eleven-level city from the planet's powerful surface winds, and underground pathways connected it to nearby sinkholes and settlements that served as secondary access points.
The city encircled the entire Pau Sinkhole, with its governmental, civic, and ceremonial buildings located on the uppermost Civic Level. The Port Administration oversaw this level. In contrast, the lowest Mining Level extended into the bone mines and the deep caves at the sinkhole's base, which were inhabited by resputi and other creatures.
The complex tidal forces on Utapau, resulting from the planet's nine distant moons, generated significant currents in the world-ocean that existed beneath the planet's outer crust. These currents, in turn, triggered groundquakes that caused sections of the surface to collapse, forming subterranean sinkholes and chasms due to stress fractures. The native Pau'ans and Utai constructed underground havens within many of the sinkholes on Utapau's single, most stable continent. The Pau Sinkhole was one of these, and it became the site of the vertical settlement known as Pau City. The inhabitants extracted minerals from the waters, grottoes, and pools of Coranth found in the lowest Mining Level.