The building on the left is the Lupanar brothel. It looks like a nondescript building. As a trading town large numbers of people specially traders visited the town. To lead visitors to the brothel, phalluses were engraved on the road surface or on the walls of stone set in the buildings. The phalluses were visibly set on the basalt stone and all you need to do is follow its direction.
As I entered the building I find myself in an enclosed space or chamber. No windows and ventilation. Alongside the chamber are cubicles where the ladies would conduct their business. The Lupanar had 10 stone beds with mattresses. Reminds me of the animated TV show The Flintstones in the stone age setting.