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.
Lechuguilla Cave
The cave was visited infrequently after mining activities ceased. However, in the 1950s, cavers heard wind roaring up from the rubble-choked cave floor. Although no route was obvious, people concluded that cave passages lay below the rubble. Led by Dave Allured, a group of cavers from the Colorado Grotto gained permission from the National Park Service and began digging in 1984. Since the breakthrough into large walking passages occurred on May 26, 1986, explorers have mapped over of passages, making Lechuguilla the eighth-longest cave in the world and fourth-longest in the United States. Lechuguilla was also the deepest known cave in the continental United States until the exploration of Tears of the Turtle Cave in 2014. Drawn by the cave's pristine condition and rare beauty, cavers come from around the world to explore and map its passages and geology.