And yet, some corners of the Earth still remain essentially uncharted by Western travelers. Tsingy de Bemaraha National Park // MadagascarNamed for the unique, massive limestone formations known as tsingy (Malagasy for “walking on tiptoes”), this 600-square-mile national park and wilderness preserve is located on Madagascar’s western edge. Fiordland National Park // New ZealandMilford Sound in Fiordland National Park. miralex/iStock via GettyNew Zealand’s largest national park was shaped by glaciers and contains some of the country’s oldest rocks. Son Doong Cave // VietnamThe world’s largest cave contains its own river and even a jungle.