Chinese authorities have not disclosed the location of artist and social activist Ai Weiwei since detaining him on Sunday at Beijing's airport. The Communist government in China has been stepping up arrests of political dissenters following uprisings in the Middle East.

The internationally-known artist, a co-designer of the Olympic "Bird's Nest" stadium whose art has been shown in galleries and museums worldwide, is a vocal critic of Chinese politics and has been arrested before.

Prior to his disappearance, Ai sent out daily political messages to his 75,000 followers on Twitter. His Twitter account has not been active since Sunday, his cell phone is turned off, and his wife has not been informed of his whereabouts.

Currently, Ai's “Sunflower Seeds” exhibition, a commissioned installation of more than 100 million porcelain sunflower seeds hand-painted by more than 1,000 Chinese artists, is on display at London’s Tate Modern.

How did this high-profile artist become a marked man in China? The Christian Science Monitor breaks down his story here.