Via the "Room of the Columns", it is possible to access the Cryptoporticus. This long underground corridor is covered by a segmental barrel vault and was originally lit by four lightwells, now filled in. Remains of meander motifs, painted in bright colors, are still visible on the ceiling. They probably belong to an earlier decorative phase (2nd Pompeian style) for they were later covered with a layer of white stucco. The entire surface of the walls is severely worn and bears evidence of graffiti: among them is still clearly recognizable the stylized image of a knight. As in the other rooms of Casa Bellezza, the floor of the Cryptoporticus is covered by a layer of cocciopesto, comprising lime mortar mixed with stone fragments, in this case mostly palombino marble and slate. Along the base of the walls runs a small channel that collected rainwater entering through the lightwells.