I've seen the topic of Earth Crust Displacement (a.k.a. Pole Shift Hypothesis) brought up various times in science-fiction stories and at least one movie (2012). The idea is that somehow the crust of the Earth can become unstuck and shift pretty severely and move landmasses to completely different parts of the globe.
The supporting points usually cited as evidence are that Einstein believed in it and that mammoths frozen in arctic ice have been found with the remains of tropical vegetation in their stomachs, indicating that what's now the arctic used to be at a much lower latitude and moved up north very quickly. This second assertion, if it's actually true, would be very interesting.
The concept seems to fail the common sense test, though. When you consider that the recent devastating earthquakes in Haiti, Chile and Japan were caused by the earth's crust shifting by a few feet each, extrapolation leads to the conclusion that a shift of a few thousand miles would cause quakes of apocalyptic magnitude that would most likely have torn apart both the bodies of the mammoths in question and the ground they were standing on.
Is there any reality to this concept, or is it just an idea that some scientists thought up back before they knew as much about the way things really work as they do now?