Something Landed In Antarctica

What created this massive Antarctic feature?

Why can’t we view the south pole on digital maps or photos? It’s blacked out. What exactly happened during operation high jump? They were attacked by who? Who could repel almost 5000 American soldiers, 13 ships, and 33 aircraft right after WW2?

It’s strange that it’s the only place in the world where almost every country has agreed to keep it off limits to ‘regular’ people.