This picture book shows readers what goes on inside 18 of the world's largest buildings and machines. Each illustration is based on the actual plans or architects' drawings so that readers know they are looking inside real structures - not a figment of some artist's imagination. Two of these illustrations are printed on fold-out pages which are a metre wide. Packed around the cross-sections are facts about each diagram which include a medieval castle, a galleon, a coal mine, helicopter, steam train and space shuttle.