The portico behind the columns was raised by a few steps as an inclination natural to the street was not possible here. On the left after the mosaics the small building of which only the base remains is known as the Octagon, so named because of its eight sides. The structure is the monumental tomb of the daughter of one of the important persons of the city.
The tomb chamber lies lower and is separated from the upper structure by a low vault. The entrance of the chamber was in the shape of a dromos and remained between the houses behind. In the tomb chamber there is a simple sarcophagus made of andesite.
The Octagon was surrounded by richly carved columns and had a roof in the form of a pyramid. The architectural materials of the building which is not yet restored lie near it.
The inscriptions visible on the same side after passing the Octagon are the decree of Emperor Tiberius relating to the restoration of the city and particularly of the city walls after the earthquake of 17 AD. The building following this is a Byzantine fountain conctructed on top of a monumental tomb which lay in the same place. The outer side of the walls of the fountain's pool have lozenge shaped decorations with crosses in the middle, a most significant element of the Byzantine period.