How hydrogen bombs compare to atomic bombs, and how scientists created the most destructive weapon ever

• Hydrogen bombs and atomic bombs are both nuclear weapons that can cause mass destruction.
• Most US nuclear weapons today were made in the 1950s and 1960s and are H-bombs.
• H-bombs are more powerful, flexible, and cleaner than a-bombs but they're also more complex to make.

The atomic bombs dropped by the United States on Japan in 1945 remain the only nuclear weapons ever used in warfare.