Tibetans in India on Sunday waved the flag of their homeland in protests marking 65 years since a failed uprising was crushed by China, driving the Dalai Lama and thousands of compatriots to flee. Leaders warned of an "existential threat" to the decades-long struggle by Tibetans in exile to win greater autonomy for a homeland many have never seen. On Sunday, hundreds of Tibetans gathered in the northern Indian hill-town of Dharamsala, the adopted home of the Dalai Lama since he fled Tibet days after the March 10, 1959 uprising.