On Earth: In this epic spectacular, the BBC Natural History Unit use a brand new approach to delve deep into the natural world and explore its most critical dimension - time. "24 Hours on Earth" travels moment by moment through a virtual day and celebrates the most extraordinary and spectacular examples of how animals and plants are adapted to exploit the 24-hour cycle. The two-part series features returnable characters that show the huge highs and desperate lows they face across a single day in the wild. It celebrates the most mind-blowing adaptations that life uses to exploit tiny windows of time.