The earliest portions of Chichén Itzá were dedicated to Chac. Many of the earliest buildings at Chichen have three-dimensional Witz masks embedded into their veneers. They were made in stone pieces, with a long curly nose. On the edge of this building can be seen three Chac masks; also take a look at the building called the Nunnery Annex, which has Witz masks in it, and the whole facade of the building is constructed to look like a Witz mask.
Mayanist Falken Forshaw reports that "What used to be called Chac masks are now thought to be "witz" or mountain deities that inhabit mountains, especially those at the midpoints of the cosmic square. Thus these masks bestow a quality of "mountain" to the building."