Presenter and naturalist Steve Backshall has travelled the planet in search of animals for his Deadly 60 list. However, it wasn't just the creatures he was seeking that were potentially lethal; sometimes the locations themselves were the biggest challenge. Two of the toughest environments were the frozen tundra of Alaska and the steaming rainforests of Brazil. In this programme, Steve and the team show how they coped with filming in temperatures below minus 20 and in the humidity and heat of the unforgiving jungle in order to capture the incredible wildlife that call these places home.