[Lee Stewart]

Le Palais Idéal is an 85-foot-long, 33-foot-high castle 30 miles south of Lyon made from rocks that a 19th-century French postman picked up during his mail route over the course of 34 years. Despite having precisely zero formal architectural training, he built the massive structure himself, complete with pillars, grottoes and flying buttresses—and visitors still go out to view it today.