Sistema Cheve

Sistema Cheve (Cueva Cheve, Sistema Cheve) is a deep cave located in the Sierra Juárez mountain range in the southern Mexico state of Oaxaca. As of June 2023, its deepest point has been measured at 1529 m deep, This makes it the second deepest known cavern in Mexico and the Americas, as well as the world's 11th deepest cave. More than 55 mi of passageways have been mapped within the cave.

, the present limit of exploration in Cheve, at 11.77 km from the nearest entrance, represents one of the most remote locations ever attained inside any cave on Earth. The logistics of reaching this point are enormous: more than two kilometers of rope need to be rigged and seven underground camps established. Cheve is the deepest proven freshwater hydrological system in the world. Temperatures in Cheve are moderate, ranging from 8 to 11 C. It has been most thoroughly explored under the leadership of caver Bill Stone.

Exploration history
Cheve was discovered in the mid-1980s by Bill Farr and Carol Vesely. Since then it has been pushed to the depth of 1529 m, making it the second deepest cave in the Americas. As of 2015 the cave system had the greatest proven depth potential in the world as proven by a dye trace from its main entrance to the resurgence 2547 m lower. The terminus of the main Cheve system is a large breakdown pile reached after diving through two sumps. It is just over 9 km from the entrance, making it one of the most remote underground locations on Earth. Due to the logistical difficulties of continuing exploration from this point, expeditions are focusing on finding mid-way entrances that might provide a quicker route into the middle Cheve system.

On March 1, 1991, Indiana caver, Christopher Yeager, made a fatal mistake while rappelling the 23 m drop in Cheve. Eleven days after the accident, Yeager was buried in a passage near where he fell. On February 8, 1992, almost a year after his death, a team of Yeager's caving friends used ropes and pulleys to pull his body to the surface which was returned to his family in Indiana.

In 2004, an international caving expedition led by the U.S. Deep Caving Team discovered a new cave they named J2. The entrance of J2 located 5 km northeast of the Cheve entrance. J2 appears to head in the direction of Cheve Cave, with a predicted intersection beyond the tunnel collapse that stopped the team in 2003. Current expeditions are underway to find a connection between J2 and Cheve Cave, which will produce a cave system more than 2 km in depth. The integration of the entire system will produce a 2597 m deep cave and would represent the deepest cave in the world.

During the years 2017, 2018 and 2019 Cheve Cave reached 55 km in length and a depth of 1524 m compared to the Palomitas cave entrance

In 2021, an entire new section of the cave was discovered, increasing its known length to 76735 m and its depth to 1536 m.

The 2022 National Geographic TV film "Explorer: the Deepest Cave" documents the further exploration of the cave in 2021 as it was taking place by Bill Stone and a large team. The exploration team discovered that the cave appeared to end in a terminal sump. Cheve possibly continues down a drop. However, the expedition ran out of bolts and rope, and they could not navigate the drop without safety equipment.

Archaeology
Pre-Hispanic peoples used Cheve Cave for their ceremonial practices. In the Cuicatec region, most beliefs focus on a mystical figure called Señor del Cerro ("Lord of the Hill") who dwells in Cheve and cures souls is said to reside there. Numerous Cuicatec artifacts have been found within its passages. On January 24 and 25, 1988, the Cheve Archaeological Project (CAP) led by American archaeologist Janet Fitzsimmons in cooperation with archaeologists from the Instituto Nacional de Antropología e Historia (INAH) Oaxaca division, explored, recorded and mapped portions of the cave. They discovered impressive jade beads, a wooden mask, in situ vessels, buried human remains and obsidian blades, believed to have been used in bloodletting ceremonies. The greatest find of the survey was a turquoise mosaic tablet that was discovered in Chamber 1 of the cave, named the Cueva Cheve Tablet. The tablet dates to the Late Postclassic Period (1250–1500 AD). One quadrant pattern includes a battle scene with winners and losers. The cave was also likely used from the Classic Period (250–750 AD), and evidence that the cave continues to be used ceremonially today by the local Cuicatecs. In the spring of 1990 and 1991, three archaeological chambers in the cave were excavated by a team of speleologists and archaeologists from the Instituto Nacional de Antropología e Historia (INAH). Cheve quickly gained notoriety as the deepest cave in the Americas and foot traffic to the cave increased significantly. A decision was made to take the artifacts to the Oaxaca Regional Museum of INAH so they were not looted and to prevent further humidity damage.