Monks and nuns in Tibet protest over detainees unaccounted for after nearly two years.
Tibetans in China risk persecution by praying for a good outcome to a meeting between their spiritual leader and the U.S. president.
Two Nobel Peace laureates hold White House talks, despite Chinese warnings.
Authorities launch a manhunt and offer a major reward.
President Barack Obama says he will meet with the Dalai Lama, as talks stall between the Chinese government and the Tibetan government-in-exile.