The Fukuryu Maru (Lucky Dragon) was a small Japanese tuna boat, fishing about 90 miles east of Bikini at the time of the BRAVO test.
The 23 man crew first noticed something was wrong when the "sun" began to rise in the west.
"We watched the dazzling light, which felt heavy. Seven or eight minutes later there was a terrific sound -- like an avalanche. Then a visible multi-colored ball of fire appeared on the horizon."
The blast was 15 Mt, twice as powerful as US scientists had expected.
About two hours after the explosion radioactive ash made up of vaporized coral began to fall on the ship. Several crew members collected bags of it as souvenirs. Within hours, the crew members began to experience burning and nausea.
Several hundred inhabitants of the Marshall Islands in the Pacific, as well as nearly 30 US personnel connected with the tests, also became ill from the nuclear fallout.
Upon returning to Japan, many were hospitalized and one eventually went into a coma and died. Though the US denied responsibility, they issued an apology and paid $2 million in compensation.
In 1976 the Lucky Dragon museum opened in a specially constructed building near Tokyo Bay. The ship itself is the main exhibit. An estimated 300,000 people visit the Lucky Dragon museum each year.