One of the things that draws me back to the far North and the far South is the wildlife - the Arctic and Antarctic each have their own unique collections of birds and mammals.
In the far north polar bears, whales and walrus turn up on everyone’s wish-list - and are relatively easy to see (given a little bit of patience and some good guides).
Further South there might not be any polar bears to see, but here are penguins and seals and whales too.
The Arctic has always had a resident human population which has over the centuries made the wildlife (rightly) cautious of people. Most of the Arctic wildlife chooses to give us a wide berth, with the exception of the polar bears who regard us as Goretex-wrapped snacks.
The Antarctic is a different case. The Antarctic has never had a proper resident population and with the exception of a 50 year period in the middle of the 20th Century, when whaling and sealing were an industrial scale activity, we’ve tended to leave the mammal and bird populations well alone. This has meant that the mammals and birds tend not to see us a threat - and provided you don’t move too suddenly the birds particularly will come right up to you - wide-angle wildlife photography really is an option.
There are always exception to this. We (collectively) almost completely killed off the Antarctic Fur Seal in the cause of 1920s fashion - since then the fur seal population has recovered dramatically, so much so that some of the beaches in South Georgia are difficult to land on during the pupping season. The fur seal pups seem to be born with sharp teeth and a pretty mean attitude - at least part of me thinks there is a species memory from a hundred years ago, and they’d like some payback!
The other amazing aspect of the Antarctic (and South Georgia in particular) is the sheer size of the wildlife colonies. Other parts of the world might have greater species diversity, but very few have the massive colonies. The sight, sound and smell of 400,000 King Penguins on one beach isn't something you forget in a hurry.