PICK OF THE DAY
Leonardo's Dream Machines
Leonardo da Vinci produced thousands of drawings for many inventions, from his famed helicopter to more fantastical contraptions. In the first of two programmes, experts attempt to turn two of his most imaginative and daring designs for a glider and a crossbow into reality.
National Geographic, 8pm
Four young explorers document their five-month quest to be the first to travel the length of the Yenisey River. Travelling through Mongolia and Russia and finishing high above the Arctic Circle, the Canadian and Australian team use only kayaks, a raft and a crude boat to battle their way through storms and floods.