Cai Guo-Qiang is one of the most important Chinese artists to have emerged internationally in the 1990s. Best known for his spectacular firework projects at locations ranging from museum entrances to the sites of land art works such as Robert Smithson's Sprial Jetty, Cai has explored a diversity of media and artforms. These have included works such as an extension to the Great Wall of China, designed to be seen from outer space by extraterrestrial...