(CNN) — A mysterious ice age structure made from hundreds of mammoth bones has been discovered in Russia.

This isn’t the first mammoth house to be found in Russia, but it is the oldest and largest.

It measures 41-feet across and was built about 25,000 ago.

Scientists say hunter-gatherers used the bones from about 60 mammoths to build the large circular structure.

Researchers excavated the site in an attempt to understand why it was built.

Inside the circle, they found evidence that wood was burned inside it.

But overall, there are no signs of long-term habitation inside the structure.

More details about the findings were published this week in the journal antiquity.