Caves of the Mendip Hills Caves of the Mendip Hills The caves of the Mendip Hills are formed by the particular geology of the Mendip Hills: large areas of limestone worn away by water makes it a national centre for caving. The hills conceal the largest underground river system in Britain. The hills consist of anticlines of Carboniferous Limestone lying over Devonian Old Red Sandstone, with the sandstone exposed on the summits. When a surface stream running off the sandstone reaches the limestone it sinks below ground through a "swallet", (also known locally as a "slocker"), continuing on its way down towards sea level by
Borra Caves which provide views of the formations. The Araku valley, a hill station about from the Borra Caves, is also a tourist attraction for people visiting the caves. November and December are ideal months to visit the caves. Borra Caves The Borra Caves, also called "Borra Guhalu", are located on the East Coast of India, in the Ananthagiri hills of the Araku Valley (with hill ranges' elevation varying from ) of the Visakhapatnam district in Andhra Pradesh. The caves, one of the largest in the country, at an elevation of about , distinctly exhibit a variety of speleothems ranging in size