When I was a kid I was totally obsessed nuclear bombs. I was fascinated by how they exploded and by calculating the range of their destructive effects. I spent many hours watching footage of nuclear tests conducted by the US, the USSR, and other countries. I had always wondered what would happen if a nuclear bomb went off in a major city of the world, like mine. Now I of course do not in any way want that to happen, but the idea has always fascinated me. Well now, thanks to the internet, there is a site where you can detonate virtual nuclear bombs anywhere on earth and see what kind of destructive effects it would have. That site is called Nuclear Secrecy.
If a 50 megaton nuclear bomb detonated in the air over the center of New York City, it would destroy almost the entire city, and it would cause third degree burns to people over almost the entire metropolitan area who were exposed. Almost every building in Manhattan would be obliterated or severely damaged. Radiation fallout would stretch for a hundred miles down wind. Casualties would be approximately 7.6 million, nearly the entire population of New York City. And injuries would be estimated at 4.2 million. The city would be unlivable, and would ultimately have to be abandoned. It would be a scene out of a nightmare. It would be, Armageddon.
The largest bomb ever to be detonated was on October 30th, 1961, by the USSR. It was called "Tsar Bomba" and it packed a punch of 50 megatons. The fireball alone was 5 miles wide, truly a monster. If that bomb had detonated over New York City it would wipe the city off the map. If such a bomb went off in New Delhi India, fatalities could reach 13.3 million. Moscow, 7.9 million. London, 5.7 million. Sao Paulo, 11 million. Mexico City, 10.6 million. Los Angeles, 3.9 million. These entire cities would be obliterated and unlivable.
If playing around with such scenarios tickles your fancy, try going to the site nuclearsecrecy.com. There used to be a 3-D version where you could see the mushroom cloud over the city but it requires the Google Earth plugin which has for some reason been depreciated. I hope they get that back up and running.