At 6:45 a.m. on March 1, 1954, the earth rumbled beneath 10-year-old Jalel John’s feet as she stood on Ailuk Atoll in the Marshall Islands. Above her, half the sky turned strange colors. She remembers, in particular, the reds—the uncanny shades of red.
Within six minutes, a mushroom cloud reached 130,000 feet overhead, pulling with it the pulverized coral of islands. Left behind was a crater that measured more than a mile wide and 250 feet deep, vast enough to be visible from space. Some 350 miles away from the blast, John experienced the largest thermonuclear explosion that the U.S. military would ever detonate, a test known as Castle Bravo. (It reached a yield of 15 megatons; in layman’s terms, that’s 1,000 times more powerful than the bomb dropped over Hiroshima.)
Then came the fallout.