Bitcoin billionaires Tim Draper and the Winklevoss twins have backed a start-up dubbed “Colossal” that is aiming to resurrect woolly mammoths as part of the effort to fight climate change. The “de-extinction” focused bioscience firm closed a $15 million funding round on Sept.13, which was led by Legendary Pictures founder Thomas Tull. The round also included participation from Peter Diamandis of Bold Capital, Jim Breyer of Breyer Capital and Tony Robbins, the famous “self-help guru” with a net worth of around $500 million.