One of the many Mithradeum in Ostia, this one is found behind/below the Baths of Mitheras (Fantastic fantasy when naming that place. Mitheras was an eastern god connected to seven spheres and the cult was open only to men and mainly involved sharing meals and ritual sacrifice of bulls.
The Casa delle Volte Dipinte, the house of the painted vaults. This is one of the best preserved buildings in Ostia and you need a permit to go in.
Roses in the ruins, close to the ancient seafront.
Well this was found in a bar and is supposed to depict a female (?) dancer. I have no idea what so ever why anyone would want this picture in a bar.
This mosaic was found in the Garden House, a large Hadrian (117-138 AD) domestic complex, much like modern apartments. Curiously enough this is the only mosaic found in the large open area around the houses and nobody knows why.