- Clear Lake, Lake County, California1
- Cliff Palace, Mesa Verde National Park, Montezuma County2
- Cochiti Pueblo, Sandoval County, New Mexico3
- Cologne, North Rhine-Westphalia, Germany1
- Colombo, Sri Lanka1
- Colosseum, ancient Rome2
- Copán (ruins), Honduras1
- Corral Harbor, San Nicolas Island, Southern Channel Islands1
- Coulterville Road, "Upim" Big Meadow, Yosemite National Park3
- Crater Lake, Klamath County, Central Oregon1
- Craters of the Moon, Idaho1
- Crow Agency, Crow Reservation, Big Horn County3
- Crow Reservation, Big Horn County, Montana2
- Debra Damo Monastery, Tigray Region, Ethiopia1
- Deer Creek, Tehama County, California3
- East of Big Eddy, Celilo Canal, Oregon1
- Ecuador30
- Edwards Field, UC Berkeley12
- Egypt1
- Eua Island, Tongatapu Island Group, Tonga1