Athens is the capital city of Greece and the birthplace of democracy. Your first stop should be the Acropolis, a UNESCO World Heritage Site and symbol of Ancient Greece. The Acropolis features several ancient ruins, including the Parthenon, the Erectheion, and the Temple of Athena Nike. Don't forget to visit the Acropolis Museum to learn about the history of the ancient citadel. In the evening, head to the Monastiraki neighborhood for some traditional Greek food.
Delphi is a UNESCO World Heritage Site and was considered the center of the world by the ancient Greeks. Visit the Temple of Apollo and the Delphi Archaeological Museum to learn about the history and mythology of ancient Greece. Don't miss the opportunity to see the Delphi Theatre, the Tholos of Delphi, and the Stadium. Spend the night in the picturesque town of Arachova to experience modern Greek culture and nightlife.
Olympia is another UNESCO World Heritage Site and the birthplace of the Olympic Games. Visit the Archaeological Site of Olympia to see the ancient stadium, the Temple of Zeus, and the Philippeion. Don't forget to see the Olympia Archaeological Museum to view ancient artifacts related to the Olympic Games. Spend the night in the nearby town of Pyrgos.
Mycenae is a UNESCO World Heritage Site and was one of the major cities of ancient Greece. Visit the Mycenae Archaeological Site to see the Lion's Gate, the Treasury of Atreus, and the Ancient Theatre of Mycenae. In the afternoon, head to the Ancient Theatre of Epidaurus, another UNESCO World Heritage Site, to see one of the best-preserved ancient theaters in Greece. Spend the night in the nearby town of Nafplio.
Spend the day exploring Nafplio, a charming seaside town with Venetian and Ottoman influences. Visit the Palamidi Fortress and the Bourtzi, two 18th-century fortifications. Don't forget to stroll around the picturesque streets of the Old Town, where you can find several restaurants and shops. In the evening, head to the nearby seaside village of Tolo for some fresh seafood.
Take a day trip to Hydra Island, one of the most beautiful and exclusive Greek islands. Walk around the car-free town of Hydra, where you can see beautiful stone-paved alleys and traditional mansions. Visit the Historical Archives Museum, the Ecclesiastical and Byzantine Museum, and the Historical Museum of Hydra. Don't forget to try some local sweets, such as amygdalota and pasteli. Take a ferry back to Athens in the evening.
If you have more time, consider visiting other Greek islands such as Santorini or Mykonos. If you have less time, you can skip Mycenae and Epidaurus and spend more time in Athens or Hydra Island instead. Make sure to wear comfortable shoes and bring sunscreen and water, as most of the attractions are outdoors. Don't forget to try traditional Greek cuisine, such as moussaka, souvlaki, and tzatziki.