AdvertisementThe U.S. Isn't Buying North Korea's Claim Of An H-Bomb TestJanuary 06, 2016Geoff BrumfielfacebookEmailCastle Romeo was an American hydrogen bomb test in March 1954 at Bikini Atoll in the Pacific. It was 11 megatons, or roughly 1,000 times more powerful than North Korea's test on Wednesday. North Korea says it was a hydrogen bomb test, though the White House says it doubts the claim. (Getty Images)