The end of the world has always been a popular subject, as you can tell by looking at the artwork below. Some of these were done for magazines and some of them for paperbacks but what they all have in common is that they deal with the end of the world as we know it.
Presented for your consideration, pulp art of the apocalypse:
Fantastic Adventures was an extremely successful and influential pulp magazine that was published from 1939 to 1953. They published a combination of fantasy, horror, and adventure, all distinguished by a more light-hearted approach than some of the other pulp magazines of the era.
Even better, Fantastic Adventures was one of the few pulp magazines to give proper credit to its cover artists: