 It dates to the reign of Uaxaclajuun Ub'aah K'awiil and is the best preserved of the buildings from his rule.The superstructure of the building has an interior doorway with an elaborate sculpted frame and decorated with masks of the mountain god "Witz".The outer doorway is framed by the giant mask of a deity, and has stylistic similarities with the Chenes regional style of distant Yucatán.