structure 5d-91, the central structure, is a twin facade structure facing both north and south. this building is the main section of the southern range and is the largest building in the whole plaza of the seven temples. the structure consists of three parts, a stepped basal platform with five levels, the superstructure containing the building's rooms, and a roof comb. the structure was accessed via wide symmetrical stairways on both the northern and southern sides. it has been restored by archaeologists and possessed a long gallery that was later split into three rooms with the addition of thick dividing walls. this structure has small sculpted anthropomorphic masks on each of its corners and possibly two further masks in the centre of the north and south sides, although very little remains of these. it possesses a small roof comb that is decorated with a further ten masks. the masks are still partly visible and show feather decorations and, in some cases, necklaces. the masks have stylistic similarities with sculpted monuments at the city. the roof comb was built from five small vaulted sections, each with a mask on both its north and south face. structure 5d-91 had 6 doors, with three on the north side and three on the south. the three rooms had small doors linking them; and each room had a lower ceiling at each end, with a higher section in the middle. structure 5d-91 has been dated to the late classic.