The third cliff dwelling that I visited while at Mesa Verde was Spruce Tree House, which does not require a ticket as it is a self-guided tour. Rangers are on-site at all times to answer questions and keep and eye on visitors.
It is the third largest of the cliff dwellings and contains about 130 rooms and 8 kivas (kee-vahs) built into a natural alcove 216 feet wide at its greatest width and 89 feet at its greatest depth. It is thought to have been home for about 60 to 80 people.
The black areas on the underside of the rock were caused by smoke from the fires they used to cook with and keep warm.