According to the Natural History Museum, London, the ground upon which we build is anything but solid. The Earth Gallery illustrates how rocks flow, melt, shatter, are squeezed and folded. But more than that, the continents that support the earth’s civilizations are in constant motion. Hundreds of millions of years ago the continents were joined, but now they are dispersing ever so slowly. Once, the east coast of South America nestled neatly against the west coast of Africa. Now, separated by the Atlantic Ocean, they lie 9600 km apart. The idea that buildings are founded upon stationary ground is an illusion. From the perspective of geological time, the earth’s crust is in a state of dynamic flux.