The Venus of Willendorf is possibly the world's most famous Ice Age creation. Although just one of many figures carved in the same style across Europe around 30,000 years ago, she has come to stand for all of them. However, her origins are unknown – although named after the place where she was found, the rock she is carved from is not local to that area. Now that rock has been identified. In the process, a little about the figurine's design has been revealed.

The Venus is made from the rock oolite. Willendorf, Austria, has no oolite deposits nearby so it was immediately obvious she had made a substantial journey for a time when all travel was on foot. However, for more than a century anthropologists had no way of knowing how far she had come.

However, a collaboration between geologists and anthropologists has concluded in a paper published in Scientific Reports that the Venus is almost certainly made from northern Italian oolites. In other words, not only was she carried 400 kilometers (249 miles) as the crow flies, but Western Europe's highest mountains lay in between, likely making for a much longer journey around.

The discovery was made possible by examining the Venus's innards. There is no way any scientist would get permission to open up such a priceless item, but Dr Gerhard Weber of the University of Vienna and co-authors used a sort of X-Ray compilation known as micro-computed tomography. This allowed them to see the Venus's interior as precisely as if they could have got a microscope inside.

"Venus does not look uniform at all on the inside. A special property that could be used to determine its origin," Weber said in a statement. 

The tomography revealed remnants of Jurassic shells within the stone, along with a few larger, very dense grains known as limonites.

The team then obtained samples of oolites from across Europe, cutting them open to study under microscopes in the way they couldn't do for the Venus. Based on the grain sizes, the Venus could not be from the closer oolite deposits, but was a perfect match for those from Lake Garda, Italy. Crossing the Alps would be difficult at any time, and perhaps impossible at a time when the last glacial was approaching its peak. It is more likely that Venus was carried on a great arc around the mountains, following river valleys and the shores of the Adriatic most of the way.

The only other oolite that comes close to being a match is from eastern Ukraine, 1,600 kilometers (994 miles) away. Symbolic as such a journey would be now, indicating Ukraine's deep European connections, the authors consider it unlikely.

What we don't know is if the Venus moved rapidly to where she was found, perhaps as part of a series of exchanges, or if she was carried along on a multi-generational migration.

Although the other carvings known as Venuses replicate many of the Venus of Willendorf's large breasts, buttocks, and thighs, her composition is unique. Most other known examples are carved from ivory or bone, with a few from stones other than oolites. Indeed, two ivory figurines were found with the Venus. However, the choice makes sense. The oolite of which the Venus was made is very porous, making it relatively easy to carve compared to most rocks.

The authors also concluded hemispherical cavities on the Venus's neckline and right leg were left behind by shell fragments that dissolved, rather than having been made deliberately, as some have suggested. Other cavities are probably from the breaking off of limonites, one of which was enlarged to make the navel.