Archaeologists have uncovered a fascinating discovery in Spain - a crystal dagger dating back 5,000 years. The incredible weapon was found in the megalithic tomb of Montelirio tholos, which is located in southwestern Spain. Alongside the dagger, the team of researchers found 25 arrowheads and cores for making the weapons. Rock crystal, which is commonly found in late … [Read more...] about A 5,000-Year-Old Crystal Dagger Was Discovered Buried in Spain By Researchers