Season 4 - Episode Guide

Dick and Dom's quest takes them into the frazzling, windy and fast-flowing world of renewable energy. Heading deep into the searing Nevada desert, the pair discover how the sun's energy could keep the world powered forever, at the iconic Hoover Dam, they uncover the genius behind how a vast lake can generate epic amounts of power, before they put all they have learnt to the test with their own suitably wacky take on a power station.

Dick and Dom are under attack in this high-octane tour through defensive engineering. The boys delve into the work of three geniuses whose ideas have given us impregnable castles, reinforced concrete bunkers and may one day protect planet Earth from asteroid attack! To top things off, they head to the seaside for a mega-sized game of smash the sandcastle.

Dick and Dom turn their attention to the incredible world of monster bridges, tracing the genius ideas that have taken us from ancient Roman arches to elegant cable-stayed suspension spans, to a future where we may see bridges 3D-printed by robots. In their challenge, the boys join the Royal Engineers for an army bridge-build race... complete with a severe dressing-down for the loser.