Several dramatic glaciers spill over into the arms of Lake Argentino, having flowed from the southern Patagonian icecap, which is about 250 miles long. Our boat trip took us first to see the Upsala Glacier, at a distance of 4 km, because it has a large field of icebergs in front of it. Next we disembarked for a walk through a forest to Onelli glacier, and then back aboard the boat to travel to the truly spectacular Spegazzini glacier, which we were able to approach close to the calving face.