Z-City Ghost Town

The Z-City Ghost Town (Z市ゴーストタウン, Zeddo Shi Gōsuto Taun) is a large uninhabited neighborhood located on the east side of Z-City.

Overview
When cases of high-level monsters appearing in the neighborhood increased all of a sudden in the last few years, all citizens supposedly moved in masses to the center. As a result, the whole neighborhood was deserted and it's now a ghost town, but with the critical infrastructure like electricity and water supply intact.

Among the normal citizens of Earth, it's just supposed to simply be some abandoned ruins on the outskirts of Z-City.

Saitama's Apartment
Saitama's Apartment (サイタマのアパート, Saitama no apāto) was the primary residence of Saitama and Genos. The apartment was also a meeting spot for the Saitama Group. During the raid on the Monster Association, the apartment is destroyed by Tatsumaki when she rips the base out of the ground.

Monster Association Headquarters
The Monster Association Headquarters is a vast maze of various underground rooms, tunnels, and caves. It is currently home to the Monster Association after its previous inhabitants, the Subterranean People, were driven to extinction due to infighting following the death of their leader.