A three year challenge to recreate the equipment used by Mallory and Irvine in their ill fated attempt to climb Everest in the 1920s revealed that they were adequately clothed, wearing an unbelievable number of layers, as shown in this list. Today, the number of layers has changed as have nearly all the materials used for Everest kit, with high tech, breathable yet waterproof fabrics and lightweight alloys. The extreme requirements of Everest are a good way to demonstrate technology and design innovation through history.