South Korean environmentalists hold a rally demanding an investigation into allegations that United States Forces Korea(USFK) secretly buried a large amount of highly toxic Agent Orange in front of the United States Embassy in Seoul, South Korea, on May 23, 2011. The allegations were surfaced last week after a U.S. television program reported, citing three military veterans, that the USFK secretly buried hundreds of drums of Agent Orange, a substance that was used extensively during the Vietnam War, at Camp Carroll in Chilgok, 300 kilometers southeast of Seoul, in 1978. [Photo: Xinhua]