Charles Hapgood came up with the "Earth Crustal Displacement theory". Hapgood's theory suggests that Earth's outer crust is able to move upon the upper mantle layer rapidly up to a distance of 2,000 miles, placing Atlantis in Antarctica, when considering the movements of the crust in the past. Albert Einstein was one of the few voices to answer Hapgood's theory. Einstein wrote a preface for Hapgood's book "Earth's shifting crust", published in 1958. This theory is particularly popular with Hollow Earthers, and can be seen as a mirror of the Hyperborean identification. In his book "Fingerprints of the Gods", author Graham Hancock argues for the Earth Crustal Displacement theory in general, and the Atlantis/Antarctica connection specifically, then goes on to propose archaeological exploration of Antarctica in search of Atlantis.