Tlacolula de Matamoros
The caves and rock shelters vary in size and what they contain. Many contain paintings and other forms of graphic representation. Contents include ceramics and stone tools. The corn materials show similarities to the first vestiges of the domestication of wheat and rye in the Middle East. One of the deepest caves is called the Cueva de la Paloma. The caves have been studied since the 1960s, especially the Cueva de Guilá Naquitz (white stone in Zapotec), which has some of the best evidence for the domestication of corn and squash, which dates back more than 10,000 years. Other caves, such as those near Yagual and Mitla confirm findings at Guilá Naquitz and show human occupation to about 8000 years BCE the sites also show similarities to the Head Smashed and Buffalo Jump Complex sites in Canada. Many more smaller caves with similar artifacts are thought to exist in the area.
Tears of the Turtle Cave
The entrance to Tears of the Turtle Cave was found in 2006. The cave passage is mostly a two to three foot wide fissure that follows a stream downward through numerous rappels. In 2014 a team of nine cavers explored new passage pushing the cave to a depth of 1629 feet and in doing so passed New Mexico's Lechuguilla Cave to become the deepest known limestone cave in the United States. Exploration continued in 2016 when teams returned to push the cave to its current known depth of 1659 feet. On those trips the difficulty necessitated establishing camp in the cave for the first time. This, along with the technical rope work, 39 degree temperature, and remote location of the cave make continued exploration difficult. A return trip is currently planned for 2019.