Modern humans began to spread across Eurasia about 45,000 years ago, but previous research showed that the first modern humans that arrived in Europe did not contribute to later populations. A new study published in Nature Ecology & Evolution focuses on the people who lived between 35,000 and 5,000 years ago and that are, at least partially, the ancestors of the present-day population of Western Eurasia, including—for the first time—the genomes of people who lived during the Last Glacial Maximum (LGM), the coldest phase of the last Ice Age, around 25,000 years ago. The team analyzed the genomes of 356 prehistoric hunter gatherers from different archaeological cultures—including new data sets of 116 individuals from 14 different European and Central Asian countries.