World marks 80 years since US dropped atomic bomb on Japan as global powers still trade nuclear threats

As the world marks the 80th anniversary of the first use of a nuclear weapon on the Japanese city of Hiroshima near the end of World War II, the planet is closer to seeing them used again than it has been in decades, experts and survivors are warning.

​ As the world marks the 80th anniversary of the first use of a nuclear weapon on the Japanese city of Hiroshima near the end of World War II, the planet is closer to seeing them used again than it has been in decades, experts and survivors are warning. Read More Breaking News, Latest News and Videos | CNN