Gerontoelia is the oldest olive tree in the world on the island of Naxos, Greece, in the village Kastri. It is estimated to be over 5,000 years old.
Gerontoelia is behind a stone wall, so I couldn't get up close (seen here), but here is another olive tree on the same grove. By size I believe it would also be thousands of years old.
Archaeological evidence and examination of fossil olive leaves in the Aegean area, inform us of the existence of olive trees 50,000 years ago.













