Series 4

Setting off from the vibrant city of Kuching, in the Malaysian state of Sarawak in North West Borneo, and the gateway to the island's vast wilderness, these pairs will tackle the most formidable race yet. Traversing prehistoric jungles and the heartlands of Borneo, to reach five check points across three countries and two continents, ultimately aiming for the sunbaked southern tip of Australia and the finish line in Melbourne.