Yemen is a land of physical contrasts, bounded by mountains, desert and sea. It includes the Socotra archipelago and various islands in the Red Sea. At the heart of the south, like a deep gash across the land, is the Hadhramaut Valley. The geology of the region intrigued the early explorers, as it continues to do today. They had to overcome considerable political and physical difficulties as well as grapple with a complex geological puzzle that had its origins in the breakup of Gondwanaland.