Visitors tour a Bell Cave at Bet-Guvrin and Maresha National Park, Israel, on June 28, 2014. The Bell Caves were hewn during the Byzantine and Early Muslim periods. The caves were used mainly as quarries and provided building material for cities on the coastal plain and for Bet-Guvrin itself. Caves of Maresha and Bet-Guvrin in the Judean Lowlands as a Microcosm of the Land of the Caves in Israel were inscribed on the UNESCO World Heritage List on June 22, 2014. This "city under a city" is characterized by a selection of man-made caves, excavated from the thick and homogenous layer of soft chalk in Lower Judea. It includes chambers and networks with varied forms and functions, situated below the ancient twin towns of Maresha and Bet Guvrin, that bear witness to a succession of historical periods of excavation and usage stretching over 2,000 years, from the Iron Age to the Crusades, as well as a great variety of subterranean construction methods. The original excavations were quarries, but these were converted for various agricultural and local craft industry purposes, including oil presses, columbaria (dovecotes), stables, underground cisterns and channels, baths, tomb complexes and places of worship, and hiding places during troubled times. (Xinhua/Li Rui)