
Swallow Holes, Sinkholes, also known as shake holes or swallow holes, occur when water seeps into solid bedrock and erodes it to the point that an underground cavity forms. When this cavity collapses, it forms a crater-like depression. Sinkholes occur all over the world — in jungles as well as cities — and can appear suddenly or gradually. The Bimmah Sinkhole, above, is located on the coast of Oman, an Arab state in the Arabian Peninsula.