Travel to Tibet needs special permission. Most regions of Tibet are not open to foreign travelers.  Traveling individually to Tibet is officially not allowed. Aside from visas for China, travelers to Tibet must also obtain permits from the Tibetan Tourism Bureau.

 
Additionally, travelers must officially be part of a group tour with a guide. Sometimes this means a couple books a tour package through an agent and sometimes this means several travelers hang out in Chengdu (see Getting There) waiting for enough people to make a group. In any case, this translates into a bit of hassle and extra money spent by the traveler, but once in Tibet, it is fairly easy to make arrangements to see the sights you'd like.