The North Sea
In geography the mental map shrinkage of the world means that China and India are no more than 15 hours away. Just after the Ice Age when sea levels were 50 meters lower tribes crossed the land bridge following Mammoth and Bison from Norway and Tunisia. It was not till later they settled. Population then was minute as the landscape supported only a few and strangers would have been welcomed rather than resented. English and Saxon villages nestled comfortably next to each other. So it is over population that threatens the human race. So a ranting priest raging against fornication may not have been wrong. Cycles can be transported virtually free from the Sex Trade Centre of Hamburg (Reeperbahn) and Amsterdam to Newcastle (North Shields). Both cruises take 19 hours.