The Greenland Iceberg stands at almost 47 miles high. It is also the tallest freestanding structure on earth. That makes it one of the most interesting places to visit, and it is also a challenge to the explorers. The challenge, it seems, starts when you try to get into the ice. This can be a problem because you will have to climb a portion of the ice that is below you to get in. This means that you will have to travel hundreds of miles through the ice to reach land you otherwise wouldn't be able.