Huge Army Tank

During World War II, Hitler commissioned Ferdinand Porsche, designer of the Volkswagen and many other cars, to design the biggest, heaviest tank possible. The thing was watertight so it could traverse water. It could cross a river, not by floating, but by crawling across the floor of the river. The problem with this tank is that it was so heavy it literally demolished the streets and foundations of nearby buildings as it passed, due to its weight and vibration.