Caves are usually formed by water eroding or dissolving the rock. Lava flowing can leave cave tunnels in the cold lava when the hot runs out. Caves can be shallow as when a rock fall near the bottom of a cliff leaves an overhanging roof. Almost anything that can live in the open can be found in these caves including birds, bears and large cats, and smaller mammals and rodents. Deeper caves are usually occupied by small animals, especially bats and insects. Because of the lack of sun, no plants grow although there apart from mushrooms

Cave popcorn can be formed by water seeping through limestone walls or splashing into caves and deposits the minerals in small bumps witch can be called cave popcorn or cave coral. Cave popcorn can be found on the floor and walls of caves. Its easy to idetifu cave popcorn because it looks just like the popcorn we eat.

A massive cave has been recently uncovered in a remote Vietnamese jungle is the largest single cave passage jet found, a new cave servay.

At 262-by-262 feet (80-by-80 meters) in most places, the Son Doong cave beats out the previous world-record holder, Deer Cave in the Malaysain section of the island of Borneo.Deer Cave is no less than 300-by-300 feet (91-by-91 meters), but it's only about a mile (1.6 kilometers) long.

By contrast, explorers walked 2.8 miles (4.5 kilometers) into Son Doong, in Phong Nha-Ke Bang National Park, before being blocked by seasonal floodwater—and they think that the passage is even longer.