Nuclear weapons and the United States

Nuclear weapons are the strongest and most powerful weapons in the world. They use nuclear energy to create a huge explosion, which can destroy whole cities. The United States is one of a few countries in the world that have nuclear weapons. The US built and tested nuclear bombs during the 1940's and 1950's, which made them the first and only country to have and use a nuclear bomb. Since then, the US has kept their nuclear weapons to protect themselves from attacks by other countries. But if the US ever used their nuclear weapons, it would cause a lot of destruction, so the US agrees not to use them unless absolutely necessary for their defense.