This via Pruned, (which possibly does itself a disservice by calling itself merely a landscape architecture blog):
Picture caption: (According to the Brookings Institution, “beneath this concrete dome on Runit Island, part of Enewetak Atoll, built between 1977 and 1980 at a cost of about $239 million, lie 111,000 cubic yards or radioactive soil and debris from Bikini and Rongelap atolls. The dome covers the 30-foot deep, 350-foot wide crate[r] created by the May 5, 1958, Cactus test.†Photo by the Defense Special Weapons Agency. Thanks, Capability B., for the link.)