History of European exploration in Tibet

The location of Tibet, deep in the Himalaya mountains, made travel to Tibet extraordinarily difficult at any time, in addition to the fact that it traditionally was forbidden to all western foreigners. The internal and external politics of Tibet, China, Bhutan, Assam, and the northern Indian kingdoms combined rendered entry into Tibet politically difficult for all Europeans. The combination of inaccessibility and political sensitivity made Tibet a mystery and a challenge for Europeans well into the 20th century.