'Tis said by some that The Fantastic Four were based on The Challengers Of The Unknown, thereby proving that Jack Kirby was the sole creator of Marvel Comics' first family, but there are difficulties with that view. Firstly, the two main similarities are that there are four in each group, and that both groups survived a crash from the skies, but there are more differences than similarities. For example, the Challs are all men and none of them have superpowers, whereas the FF are three men and a gal, who do (have superpowers that is).
Secondly, the Challs only flew in a plane and were going from one place to another in the US, the FF were in a spaceship aimed for the stars. The Challs survived an actual out-of-control crash, whereas the FF's rocket's automatic pilot took over and guided it to a rough-but-safe landing. But there's another factor to consider. The Challengers, it seems, were not created by Kirby alone, but reputedly with the collaboration of either Joe Simon or Dave Wood (or maybe even both) so that would possibly make both men as much the co-creators of the FF as Kirby.
So even if it was Jack who took the idea for the FF to Stan Lee, then it was hardly an original one dreamed up solely by himself. It's possible, though, that once Stan and Jack got together to discuss a new team book (because of the popularity of DC's Justice League Of America), Jack threw in the 'survivors' aspect, which Stan then included in his two-page synopsis for the FF's very first ish, but the truth is we'll never really know. Another thing is that the Challs motivation for their adventures was that they regarded themselves as 'living on borrowed time', but the FF's motivation was to use their new powers to help mankind. In short, the challs were thrill-seekers, the FF were inspired by altruism.
But hey, none of that matters, because we're not here to talk about The Fantastic Four - we're here to look at the 12 covers illustrated by Jack Kirby for DC. I kinda got sidetracked, but I'm sure you won't hold it against me as you ogle the dynamic and delectably drawn dozen images presented for your deliberation and delight.