Robyn Miller uncovered this intriguing photo and asked his readers to imagine what it might be: "the secret lair of Jame Bond's nemesis? Better yet... evidence of a crashed spaceship!"
But actually, it's a $239 million dome that covers the radiocative waste from nuclear explosion tests in the Bikini and Rongelap atolls. "The dome covers the 30-foot deep, 350-foot wide crater created by the May 5, 1958, Cactus test." Cactus Dome
Mark Frauenfelder is the founder of Boing Boing and the editor-in-chief of MAKE and Cool Tools. Twitter: @frauenfelder. His new book is Maker Dad: Lunch Box Guitars, Antigravity Jars, and 22 Other Incredibly Cool Father-Daughter DIY Projects