TIL that Edward Teller, the father of the hydrogen bomb, once proposed a 10 gigaton bomb. It would have been 670,000x stronger than the bomb dropped on Hiroshima, and 200x stronger than the Tsar Bomba, the largest bomb ever created. It's estimated to have been able to set all of France on fire.

https://blog.nuclearsecrecy.com/2012/09/12/in-search-of-a-bigger-boom/
https://www.reddit.com/r/todayilearned/comments/15dptn7/til_that_edward_teller_the_father_of_the_hydrogen/