Omphalos

An omphalos is an ancient religious stone artifact, or baetylus. In Greek, the word omphalos means "navel". According to the ancient Greeks, Zeus sent out two eagles to fly across the world to meet at its center, the "navel" of the world. Omphalos stones used to denote this point were erected in several areas surrounding the Mediterranean Sea; the most famous of those was at the oracle in Delphi.

Omphalos in After the Downfall
In 1893 Herr Doctor Professor Maximilian Eugen von Heydekampf took the Omphalos stone from Zeus' temple in Delphi and brought it back to the Old Museum in Berlin. In April 1945 while under siege by the invading Soviet forces, Captain Hasso Pemsel sat on the Omphalos and was transported to another, magical world.