From Britain to the Balkans, Europeans are part of one big family, scientists have discovered.
Despite being separated by thousands of miles, they have shared ancestors dating back little more than a dozen generations.
Researchers looked at the DNA of more than 2,000 people from all over the continent and found surprising similarities.
As expected, the relatedness of any two people got less the further apart they lived. But even people in the UK and Turkey were likely to have relations in common who lived 1,000 years ago.
Italians are one of the most diverse groups, say scientists, having lower levels of relatedness to one other and other Europeans.
Many eastern Europeans showed higher levels of relatedness - possibly reflecting the expansion of Slavic peoples into Europe more than 1,000 years ago.
"What's remarkable about this is how closely everyone is related to each other," said study leader Professor Graham Coop, from the University of California Davis.
"On a genealogical level, everyone in Europe traces back to nearly the same set of ancestors within a thousand years.
"This was predicted by theory over a decade ago, and we now have concrete evidence from DNA data."
The pattern found in Europe would probably also apply to the world, said Professor Coop.
"The overall picture is that everybody is related, and we are looking at only subtle differences between regions."
The scientists compared DNA from a genetics research database called the Population Reference Sample.
First cousins who have grandparents in common share long stretches of DNA, but the project looked for shorter blocks of DNA shared by cousins separated by many generations.
After identifying individuals across Europe with common DNA sequences, the scientists were able to calculate how long ago they shared the same ancestor.