It seems that the wheel has been known for a very long time, at least on this side of the big water, and that the idea did not just come to one person alone. Underwater archaeologists have played their part in bringing light into the darkness in this question. Biological materials, such as wood, are often better preserved under water than on land, especially in moorland contexts.
The oldest dated wheel-axle combination was found in Stare Gmajne in the Ljubljana bog near Ljubljana in Slovenia. The wheel was dated 3340-3030 BC and the axle to 3360-3045 BC. A somewhat younger wheel was found in the Federsee Moor in Seekirch-Achwiesen in Austria. It is about 5000 years old and is made of two parts joined together.
The Ljubljana Bog and the Ljubljanica River are due to their prehistoric finds of outstanding archaeological importance and did not just hide this oldest wheel of the world.
The bog was formed 2 million years ago. Following the last ice age 10,000 years ago, a lake formed there, which then dried out about 3,500 years ago to the extent that only vast swampy areas remained. This Ljubljana Marsh was then inhabited in prehistoric times, when it was a shallow lake and traces of prehistoric pile dwellings have overcome from that time in its marshland. There were also finds even older than the wheel, such as for instance an arrowhead used by Neanderthals. The 23 km stretch of the Ljubljana River between Vrhnika and Ljubljana and the surrounding floodplains, the Ljubljana Marshes, hold still many secrets at their bottom and research is ongoing.
In more northern regions bog finds have already brought spectacular objects to light, such as the sacrificed human beings, two-meter-high trumpet like instruments as well as weapon collections and a large sacred vessel found in the Bogs of Jutland. Similar finds were made in Oberdorla in Germany. In ancient times the Germanic tribes believed that the lakes and marshes gave access to the underworld and female goddesses like Nerthus or Perchta lived there. She guarded in winter the lost souls and came back to the upperworld in spring to revive the earth and the crops. Only a small part of these kind of bogs has yet been researched and much more can be expected to be discovered in future.