If you are really passionate about the past, discoveries and most importantly, possible theories that can lead to a greater understanding of the world, then old technology that was found will surely satisfy your curiosity. Because of wars, natural disasters and many other factors there are few explanations for what was found and little adaptations in modern languages.
So, here we have a few pieces of technology and discoveries that still remain unexplained!
This beautiful discovery is called Nimrud Lens and it was found in 1850 in Iraq. This 3000-year-old lens is said to have been used as a telescope lens by the Assyrian people who had an affinity for astronomy.