A former Tiananmen Square protestor turned U.S. army chaplain was turned away at Hong Kong’s airport Thursday as he attempted to visit his ailing mother. Xiong Yan, now an American citizen, has had several visa applications denied. He tried Hong Kong as a point of entry because U.S. citizens can typically enter the semi-autonomous territory without a visa. (In fact, he was allowed to do so in 2009.) “I’ve arrived at the border of the free world,” Xiong wrote from the airport, before he was rerouted to a flight back to the U.S.