"He roamed through the ruinous kivas"

Kiva at Spruce Tree House in Mesa Verde National Park, Colorado
Creative Commons Attribution Share AlikeKiva at Spruce Tree House in Mesa Verde National Park, Colorado - Credit: Andreas F. Borchert
A kiva is a room used by modern Puebloans for religious rituals. They are usually square-walled and underground.

Similar subterranean rooms are found among the ruins of the Ancient Pueblo Peoples, like the Keel Seel kivas described here. Ancient Puebloan kivas are usually round, and thought to have been used for spiritual and other communal purposes.

The kivas were built in proportion to the number of rooms in a pueblo, with one small kiva built for roughly every 29 rooms. Some of the larger pueblos hosted an oversized Great Kiva, up to 63 ft (19m) in diameter.