"This configuration grew in size over the years, with the small western platform finally becoming the Lost World Pyramid itself, a giant pyramid some 32 m high, square in plan with stairways on the four sides.
Part way up the stairs are giant stone and sculptured stucco masks, now in a state of severe disintegration. Enough detail remained in one or two cases to indicate that these were jaguar masks not unlike those on E-7-Sub, the central structure at Uaxactun that gave its name to this architectural configuration. At Uaxactun the masks were paired vertically, with the one below displaying Night Jaguar and the one above displaying Day Jaguar, the two manifestations of the sun god Kinich Ahau in his night and day appearances."
Peter Harrison, The Lords of Tikal, p. 56