In the 20th century, the most destructive weapon in history was invented, which one?

In the middle of the last century, atomic and thermonuclear weapons were invented and tested. Its use is based on the tremendous energy released by nuclear fission.

In 1945, the United States tested atomic bombs, erasing the large Japanese cities of Hiroshima and Nagasaki into radioactive dust. The current stocks of weapons are more than enough to destroy all life on planet Earth.