Kailasa Temple Ellora
Although all of the caves at Ellora are stunning architectural feats, the Kailasa Temple is the jewel in the crown. Carved to represent Mt. Kailasa, the home of the god Shiva in the Himalayas, it is the largest monolithic structure in the world, carved top-down from a single rock.
It contains the largest cantilevered rock ceiling in the world. How was it constructed in just 18 years with no advanced technologies available in those time ? EIGHTH CENTURY.