Shirakawa-gō

Gasshō-zukuri houses, literally "hands joined in prayer", raise a nail-free timber frame under thatch pitched at sixty degrees so snow slides off. The three or four attic levels housed silkworm rearing, the only cash crop of a valley cut off six months a year. Re-thatching a roof takes fifty to a hundred bundles of reed and two hundred people in a single day, under a mutual-aid system called yui. The village has been World Heritage since 1995.