Longyou Grottoes

A complex of 24 artificial sandstone caverns carved into Fenghuang Hill near Shiyan Beicun village in Zhejiang Province, China, covering approximately 30,000 square metres. Discovered in 1992 when local villagers drained ponds they believed bottomless, each grotto descends about 30 m underground. Every surface is adorned with uniform parallel chisel marks, and an estimated one million cubic metres of rock were removed during construction. Glazed clay pots found on the cavern floor date to the Western Han Dynasty (206 BC - 23 AD), but no historical records mention their construction, leaving their origin and purpose a profound archaeological mystery.