55,000 years ago, Neanderthals may have trekked deep into Saudi Arabia when Nefud Desert was covered by lakes and grasslands

• Researchers examined stone tools from Jebel Katefeh 1, a site beside an ancient lake near the city of Jubbah in the Nefud Desert.
• No Neanderthal bones or DNA have ever been found in Arabia, so the team relied on the shape of stone flakes to identify who made them.