This badly ruined structure was given its name by early Spanish historians who thought that its perforated roof comb resembled a pigeon-cote. In fact, this superstructure was smoothly plastered and decorated with figures and ornaments of stucco. The building is about 240 feet long and is similar to the south building of the Nunnery quadrangle in that it is broken by a large central arch leading into an enclosed plaza, in which Stephens found a fallen and broken stele.
A portion of the roof comb has collapsed since Stephens' time, and it is surprising that this is the extent of the damage, since it is actually thicker at its top than its base. This device was employed by Maya architects as both a method of perspective correction and as a means of casting deeper shadows in the stone relief work. The buildings at Uxmal all use this "negative batter," which was first reported by archaeologist Frans Blom in 1932.