That would be the Perito Moreno Glacier in Argentina that I visited in February 2014. It is still a few hundred miles north of Ushuaia, the southernmost city in the world, but it is already “more South” than the tip of South Africa and New Zealand.
A detailed post with beautiful photos and more information about this amazing Glacier can be found here.
This is what I wrote right after returning from the trips two years ago… It was an exciting experience. How time flies! Looking forward to returning to South America in the near future.