Atomium

This guide to the Atomium in Brussels starts with a 1955 wind-tunnel test that sent engineer Andre Waterkeyn's model toppling over, and the quiet fix his team bolted in before building nine 2,400-ton steel spheres balanced on one point for the 1958 World's Fair. It follows what happened once the fair's six-month clock ran out and the structure was due to come down as scrap. Listen for it while riding the tilted escalator tube toward the top sphere's restaurant.