Archaeological evidence, primarily from Pompeii and Herculaneum, and literary sources seem to indicate the existence of private "sex clubs" in some Roman homes "(domūs)". Most Romans lived in apartments "(insulae)"; the "domus" was a large, independent dwelling owned by a family of considerable means, and in Rome was central to the family's social identity. A few of these residences have rooms decorated with pornographic art not differing from that found in identified brothels; in some cases, an erotically decorated room has its own exterior door to admit visitors who would normally enter the home through the main doors leading to the atrium, where the family displayed ancestral images and other trophies of respectability.