49,000 year old Neanderthal bones have been discovered by chance in a remote, mountainous region of Northern Spain. The bones may help solve the biggest Neanderthal puzzle of all â why we are here today and Neanderthals are not. âThe Neanderthalsâ dark Secretâ revolves around ongoing investigations deep inside the forbidding subterranean cave system called El SidrĂłn. Here, Palaeontologist Antonio Rosas and Archaeologist Marco de la Rasilla are in their 11th year of excavation. Bones from at least 12 people and 400 stone tool fragments have been recovered. Weâll bring these people back from the past. Our haunting, hologram-like Neanderthal characters, will communicate to the scientists of today, as they unlock the secrets of El SidrĂłn. Many mysteries surround the site, foremost, how the bones and tools came to be here in the first place. The remains arenât weathered nor do they show signs of scavenging from large animals.