From stormy seas to the land-locked Mojave Desert, Rob Bell discovers the amazing story of how the mighty Colorado river was tamed and how the Hoover Dam was built. The presenter abseils down the canyon to find out how to help maintain the turbines, and gets his hands dirty with an alien species that threatens the dam's future.

Rob Bell uncovers extraordinary feats of lighthouse engineering on both sides of the Atlantic, tackling the world's busiest shipping lane, discovering oil rigs and setting sail in search of America's first lighthouse. Rob meets local seafarers and lighthouse keepers to hear stories of shipwrecks - discovering extraordinary feats of bravery, ingenuity and design as he continues to crack the code of these enigmatic structures.