http://www.newsweek.com/megalithic-tombs-ten-generations-stone-age-dna-analysis-1396703

DNA analysis has revealed kin relationships between more than 10 generations of Stone Age people at megalithic tombs in Ireland and Sweden.

The evidence suggests that megaliths, prehistoric large stone structures, sometimes acted as graves for kindred groups in northwestern Europe thousands of years ago. The study was published in the journal Proceedings of the National Academy of Sciences.