...In the past decade, satellite data and fossil finds have suggested that the Arabian Peninsula was not always an arid desert. Periods when the region contained lakes and lush greenery might have drawn people and animals there from Africa, according to the study's authors... in 2018, Stewart and his colleagues described an 88,000-year-old finger bone from the Saudi Arabian desert2 — one of the oldest human fossils found outside of Africa. And in 2020, they described footprints on a lake shore dating back around 120,000 years...The researchers turned to caves under Harrat Khaybar, a vast basalt plain pocked with volcanic...