Chetro Ketl, Chaco Canyon, Chaco Culture National Historical Park, New Mexico. 19-11-2011, 15:27.
"The foot drums, as the ones seen here in the Chetro Ketl great kiva, are open, rectangular masonry vaults or boxes that were standard floor features in Chacoan great kivas. If covered with planks, they may have served as foot resonators for dancers. All excavated Chacoan great kivas built in the 1000s and 1100s (with the exception of Fort Wingate kiva) have a pair of vaults oriented on a north-south axis. They rise about 24 inches above floor level and are placed between two roof beam seating pits."
R. G. Vivian and B. Hilpert, The Chaco Handbook, The University of Utah Press, 2002.
Nikon D700, AF-S Nikkor 16-35/4G ED VR, 1/30 sec, f/11, ISO 200, FL=16 mm, WB: 5400K, Warming Polarizer