If you ever go to Ushuaia you'll probably want to head to where the glacier lived a few years ago before melting away. You should not take a taxi to the chairlifts and then take the chairlifts up. You should walk the entire way, which may take you 8 hours, but it is worth it. There is a beautiful trail that will take you up the mountain to the glacier. It was one of the hardest most frustrating hikes of my life, but it was also the most wonderful place. Here's some photos of trees from that hike.
*Please click photo to make BIGGER*