Historic grove — Makri, ~10km west of the city
Inland from Makri beach, a grove of some 220,000 olive trees includes clusters estimated at 2,500 years old — massive, twisted trunks still bearing fruit every season. Post-Byzantine records already describe the grove's 'huge olive trees', which suggests the oldest specimens were already considered ancient centuries ago.
The grove is a working agricultural site, not a museum — it produces a Protected Designation of Origin olive oil, strongly fruity with a mild bitterness, sold locally and through the Kyklopas Olive Mill nearby, which runs tastings and tours through the harvest.
It's a different kind of stop from the beach or the Cyclops Cave a little further along — worth the short detour inland for anyone who wants to see what's actually growing behind the coast.