Ai Weiwei is one of China’s most well-known artists and activists. He is a strong critic of the Chinese regime and he uses his art to raise global awareness about China's corruption and authoritarianism. Due to his citizen investigations into corruption within the Chinese Communist Party and his high profile activism, Ai Weiwei was harassed, arrested, and tortured by the government until he was imprisoned in 2011. His arrest garnered widespread international attention with heads of state, international human rights organizations, and prominent members of the global art community all petitioning for his release. Upon his release, he remained subject to a travel ban and heavy surveillance. In July of 2015, his travel ban was officially lifted and he was allowed to travel overseas. Ai Weiwei’s most famous works include Study of Perspective Tiananmen Square, Sunflower Seeds, and Surveillance Camera. His recent feature documentary, Human Flow, explores and humanizes the global refugee crisis. Ai Weiwei has received numerous awards, including the Human Rights Foundation's 2012 Václav Havel Prize for Creative Dissent and Amnesty International's 2015 Ambassador of Conscience Award. He has been described as "the most powerful figure in the art world" by Art Review Magazine in its “Power 100” list.