It may look like a banana, but this curved device is actually thought to be the world's oldest pocket calendar.
Archaeologists found the calendar in Serbia and believe the moon-shaped device is around 8,000 years old.
It is made from the tusk of a wild boar and is marked with engravings thought to denote a lunar cycle of 28 days, as well as the four phases of the moon.
The archaeologists believe ancient man would have used it to work out the best time to plant and harvest crops.
The tusk was found in an area close to the town of Smederevska Palanka in eastern Serbia.
Could this be the world's oldest pocket calendar? Engraved tusk would have told farmers when to harvest crops up to 8,000 years ago