Those friendly gents above are standing inside the leg of the "tallest structure ever moved by humans over the surface of the Earth," the Troll A offshore gas platform in the North Sea. Standing nearly 1,650 feet tall, it's absolutely humongous.
Weighing over 1.2 million tons, the structure was built using 245,000 cubic meters of concrete and 100,000 tons of steel. Once it was constructed over the course of a week in Norway, it was towed 174 miles out into the sea. Yes, it was essentially like towing a skyscraper out into the middle of the ocean, but it seemed to go pretty well. Nice work, engineering. Hit the jump for a picture of the rig being towed out to sea.