Greek Island hopping is a compelling pastime, but Greek history is best discovered by traveling Greece's mainland and Peloponnese peninsula. Here is a map of Greece, concentrating on these areas.
Map of Mainland Greece with Rail Lines
Major Sites of Mainland Greece
One of my favorite sites is that of Meteora, near Kalambaka on the map, east of Igoumenista. Here monks built virtually inaccessible monasteries on the peaks of vertical spires to avoid Turkish persecution in the 14th century. A 21km walk takes you to all the major monasteries that allow visitors. The views are spectacular. Bring your camera.
Delphi, further south, is one of Greece's most intact archaeological sites. Set on terraces along the slopes of Mt. Parnassus, the setting is spectacular. Delphi was the site of the Delphic oracle and the Pythian games. It was a major center for the worship of the god Apollo.
The picture to the left is the 5th century treasury., holding loot from wars and donations to the city. It's the most impressive building you'll see at Delphi.
Delphi Vacation Rentals close to the ancient Delphi
Mr. Olympus (deTraci Regula recommends a side trip to the little-visited city of Dion).
Metsovo was known as a town of talented wood-carvers (you'll see some excellent miniature works inside some of the monasteries of Meteora), and is home to Metsovone, a smoked cheese. Metsovo sits at the base of a mountain; you can ski in winter.
And of course there's Athens, the capital of Greece.
Major Sites of the Peloponnese
If you stay in Nafplion, you can visit some of the best sites in the Peloponnese by bus or taxi: Korinth, Epidaurus and Mycenae. Longer bus journeys or tours will take you to Olympia, Sparta or Pylos. While Sparta has few remains of its powerful city-state (spartan, you know?), Pylos is the traditional home of Nestor of the Odyssey and has the best preserved of the Mycenaean palaces in existence.
Pylos, located in mainland Greece on the southwest coast of the Peloponnesus, is the site of one of the most important Mycenaean settlements. It is considered one of the best preserved and best excavated of the major palaces. It dates to the late Helladic period before 1200 BCE. -- Pylos
Getting to Greece from Venice - Or Returning
One of my favorite ferry rides is the Venice - Greece run on a ferry. You spend two nights on the boat, which gets in early in the morning to Patras (you can stop in Corfu or Igoumenista as well). Get details: Venice to Athens on a Ferry.