The Sky Disc of Nebra:

3,600 years old. Was used as an advanced astronomical clock and was found near Europe's oldest observatory in Goseck. The 32-centimeter-wide (seven-inch) bronze disc with gold-leaf appliqués representing the sun, the moon, and the stars is the oldest visual representation of the cosmos known to date. A cluster of seven dots has previously been interpreted as the Pleiades constellation as it appeared 3,600 years ago