terrifying _secreats on Instagram: "On November 6, 1971, the United States carried out the Cannikin nuclear test on Amchitka Island, Alaska, detonating a 5-megaton thermonuclear weapon nearly 2 kilometers underground. The blast released energy estimated to be around 400 times more powerful than the Hiroshima atomic bomb, making it the largest underground nuclear test in U.S. history. The explosion generated intense seismic shockwaves equivalent to a magnitude 7.0 earthquake, causing visible grou