KIVAS
    We use the Hopi term "kiva" to refer to communal rooms that are normally round and subterranean. They seem to have evolved from the pithouse after pueblos became the common domestic architecture. Their purpose(s) aren't completely clear, but evidence suggests both ceremonies and daily activities (i.e. weaving, pot making, etc.) took place involving members of the extended family, clan and/or moiety(see pp.16, 17). There is a category of kiva, the "great kiva," in which ceremony seems to have been the sole function.
    Below is a sampling with general descriptions:
 
 
Square Pit Room, Mesa Top Ruins, Mesa Verde, Colorado; PI (c. 850)
This can be seen as a predecessor of the kiva. It was part of a complex of above-ground, slab-lined living quarters. The pit room was completely below-ground with a roof and central rectangular opening at ground-level. Notice the hearth, wind deflectors and ventilator (opening at top center).

 
Kiva, Site 102, Mesa Top Ruins, Mesa Verde, Colorado; PII (c. 950)
"The kiva.... emerged in place of the pithouse. The kiva here is the earliest type. Features such as the bench (banquette), firepit (hearth) and ventilator survived from pithouse times. The four stone pillars (pilasters) on the kiva bench acted as supports for logs which formed the roof. The people made no attempt to use stone elsewhere in (this early) kiva construction."
     from Mesa Top Ruins (Mesa Verde Museum Assoc.)

 
Kivas (restored), Spruce Tree House, Mesa Verde, Colorado; PIII (c. 1175-1276)
Top left: Toward the NW entrance of Spruce Tree House is the first courtyard with two restored kivas. Notice how the roofs of the kivas form the floor of the court.

Top right: As you enter through the opening/smoke-hole, check out the pilasters (bottom l & r) which support the cribbed timbers which in turn support the roof beams.

Bottom left: Notice the top of the banquette at ~ elbow height.

 
Kivas, Cliff Palace, Mesa Verde, Colorado; PIII (c. 1209-1275)
Top left: "Even though no two of Cliff Palace's 23 kivas are exactly alike, they all follow a generalized pattern: circular in plan, generally dug beneath courtyard level...., central fireplace, ventilator tunnel on the south side, a raised air deflector, and usually six masonry pilasters rising above an encircling banquette to support a cribbed log roof. The variation among kivas probably reflects the different ritual needs and ideas of the kin groups (lineages) who built and used these distinctive Anasazi buildings."
  from Anasazi Ruins of the SW in Color, p. 98.

Upper right: Typical Mesa Verde "keyhole kiva". The recession usually is toward the south. That's quite a deflector.

Bottom left: Here, the sipapu is evident toward the lower left. The sipapu is a common kiva feature and is thought to represent the place of emegence of the people into this world.

 
Kiva, Balcony House, Mesa Verde, Colorado; PIII (c. 1200-1300)
One of Balcony House's two kivas. The ratio of kivas to rooms (2:44) is out of proportion for Mesa Verde. Compare Cliff Palace with 23:220 and Spruce Tree House at 8:114.
Pueblo Bonito, Chaco Canyon, PII/PIII (920-1120)
Upper left: The Great House
Bottom left: Kin Kivas
Upper right: A Great Kiva

 
Chetro Ketl, Chaco Canyon, PII/PIII (920-1120)
Upper left: the Great House; Upper Right: Great Kiva;
Lower left: Pillar support disks; Lower right: Tower (or stacked) Kiva