One of the things the creationists like to wave around as “proof” of creationism is the idea that whales couldn’t have evolved from land mammals because there’s no evidence of hind legs on them or their ancestors.
Except that there is, as Stephen Jay Gould pointed out many years ago, in a lengthy point-by-point rebuttal.
Go read it. It’s lovely. And it’s buttressed by some recent discoveries in the Valley of the Whales in Egypt.