3. Gangkhar Puensum Mountain, Bhutan As the world's highest unclimbed mountain, Gangkhar Puensum-- or "the three mountain siblings" --is one of the most fascinating places for rock climbers, extreme sportsmen and scientists today.
It stands at a daunting elevation of 24,836 feet- and is Bhutan's highest point.
Due to disputes with neighboring China, the country was only opened to prospective mountaineers in 1983.