Antikythera Mechanism The ancient ‘computer’ that simply shouldn’t exist

One object recovered from the site, a lump the size of a large dictionary, initially escaped notice amid more exciting finds. Months later, however, at the National Archaeological Museum in Athens, the lump broke apart, revealing bronze precision gearwheels the size of coins. According to historical knowledge at the time, gears like these should not have appeared in ancient Greece, or anywhere else in the world, until many centuries after the shipwreck. The find generated huge controversy.

www.scientificamerican.com/article/an-ancient-greek-astronomical-calculation-machine-reveals-new-secrets/