We know the Hiddekel, or Tigris, as well as the Euphrates. The headwaters of these two rivers came from a single river that went out of Eden—out of the surrounding land, not out of the garden—and then split into “four heads” at the garden, because “from thence it was parted” (this detail is not to be overlooked). There is no such headwater river in modern Turkey. The other rivers are unknown. Since the Gihon “compasseth the whole land of Ethiopia,” it is often guessed to be the Nile, but this is not geographically consistent with the other facts given, unless the land was somehow very different indeed at that time. The word is actually not Ethiopia but Cush, כּֽוּשׁ, and that might stand for some actually unknown land in ancient Anatolia—contrary to the Septuagint, which does render the word Αἰθιοπίας, Ethiopia. Similarly, the meaning of the river Pison or “the whole land of Havilah” is unknown. But perhaps the best guess is that Eden was in modern-day Turkey, near ancient Cappadocia. Going about naked there today would be a bit chilly, but God would no doubt have taken care of that issue. After all, beyond all this, we must bear in mind that all of this takes place, according to the text, before the Flood. If a worldwide flood actually took place, it would probably have changed the surface of the earth enormously. Not just river courses, but mountain ranges and entire continents might have changed.