Antikythera Mechanism
On 17 May, 1902, while exploring a 2000 year old ship wreckage, an artifact was discovered. The artifact remained a mystery for about 100 years when scientists from all over the world started researching upon it. The research says that it was ancient greek analogue computer designed by greek scientists dated to about 80 to 150 BC. The technology and the mechanism made the device incomprehensibly ahead of time that it is not possible for such advanced device to exist at that time. Some scientists believe that it was given to the Humans by some alien civilization. It could track time, predict astronomical positions and eclipses. It was the world's very first computer over 2000 years before the first computer we know. However, the knowledge used to create such an advanced device was lost in antiquity and it is not possible to create such sophisticated advanced device for another thousands of years.