This is the entrance to the tunnel to get to the elevator that takes you up to the Eagle's Nest, which is now a tea house...the little tiny bump at the top of the mountain is the Eagle's Nest...the tunnel itself is already 6000++ feet up and the house is another 400+ above that. The workers who built this built the entire road up the mountain, the tunnel and the 400 foot elevator along with the house in 13 months flat as a gift for Hitler's 50th birthday (which he only ended up going to 4 or 5 times cause he was afraid of heights)...poor workers.