Richard Hammond climbs to the top of Sydney's iconic Opera House to unlock the engineering connections behind one of the most instantly recognisable buildings in the world. He reveals how an architect's sketch, rejected by the design competition jury, was transformed into concrete and glass through trail-blazing building techniques inspired by a First World War gas mask, a set of false teeth, a collapsible puppet toy, an ancient pharaoh's chest and a 19th-century sailing ship. Show less