Pontnewydd Cave is a Middle and Lower Paleolithic (Middle Stone Age) cave site in North Wales, located in the steep valley of the Elwy river. During World War II, it was used as a bomb shelter, which didn't help the site integrity much.
Pontnewydd Cave was discovered by Boyd Dawkins in 1874, and was the focus of archaeological excavations led by Stephen Aldhouse-Green of the National Museums and Galleries of Wales between 1978-1995. Artifacts and skeletal remains identify this site as having been inhabited by Neanderthals, about 230,000 years ago.
Green HS, Stringer CB, Collcutt SN, Currant AP, Huxtable J, Schwarcz HP, Debenham N, Embleton C, Bull P, Molleson TI et al. 1981. Pontnewydd Cave in Wales--a new Middle Pleistocene hominid site. Nature 294(5843):707-713.
Jenkins DA. 1993. Interpretation of interglacial cave sediments from a hominid site in North Wales: translocation of Ca-Fe-phosphates. In: Ringrose-Voase AJ, and Humphreys GS, editors. Developments in Soil Science: Elsevier. p 293-305.