The Troll A platform:
The Troll A platform is a condeep offshore natural gas platform located ( not visible in google maps) in the Troll gas field 70 kilometers west of the city of Bergen in Norway. It is the tallest construction that has ever been moved to another position, relative to the surface of the Earth, and is among the largest and most complex engineering projects in history:
The Troll A platform has an overall height of 472 meters and weighs 656,000 tons. You may ask yourself how this thing can be 472 meters heigh as you look at the picture above. This is because the largest part of the giant structure is placed below sea level. The platform stands on the sea floor on 4 303 meters (994 feet) high concrete legs. In the pictures below you can see the structure when it was stilll above sea level and was being towed by tugs to it's final destination:
Here are some pictures of people standing at the bottom of such a concrete leg:
These people are standing more as 300 meters below sea level but the 1 meter concrete walls of the "legs"can handle this pressure. The structure was built by Norwegian Contractors for Norske Shell, and there are about 200-300 people working on this gas platform.