Battery: We all know Alessandro Volta invented in the first battery in 1800 A.D. However, the very first battery was invented at least 2000 years ago, found in Modern day Baghdad. This primitive 3 piece gadget caused considerable doubt if it could produce any real electricity.Nevertheless, when Discovery Channel's Mythbusters created a replica and tested it, they were able to produce four volts of electricity, enough to electroplate a coin.
The Freeze-Dryer: Freeze-drying or lyophilization, is the removal of water content from frozen food to create a near-perfect preservation. Freeze-dried food lasts longer than other preserved food and also becomes lighter, which makes it perfect for long distance and even space travel. While this process is thought of as developed during the second world war, The Incas of Modern day Peru used this technique at least 500 years ago