The Mani region and the Diros Caves

For those of you who have some extra time in Greece, I recommend renting a car and driving through the southern most tip of the Peloponnessos called "Mani".

"The Mani is no longer quite the remote region that it once was, far away from Athens at the very southern tip of mainland Greece, and visitors have been quick to pick up on its rugged charms. To drive around the peninsula is to discover another very distinctive part of Greece, where tall, tower houses reach into the skies. These fortified houses were built to protect the families because of the feuds that went on in this wild west of a place for centuries. But don’t worry – they’ve calmed down a bit these days." - Taken from "Great Drives in Greece"

One of the highlights in this region are the Diros Caves (which are about an hour drive from Gythio).

"Located at the top of the Mani between the town of Pirgos Dirou and Areopolis the entrance is a few meters above the sea and a beautiful stone beach. When you arrive at the Caves you buy your 15 euro ticket at the booth and continue driving to the parking lot just outside the entrance. Try to get here early especially in the summer. When you enter the cave you will walk down a stairway to an underground lake where there are boats waiting. You are given a life-vest and then each boat gets a guide who uses poles to journey through the caverns and tunnels, which are eerily lit and adorned with stalactites and stalagmites, many with interesting names. You will pass through some sections just wide enough to allow your boat, where you have to duck your head and then enter into an enormous subterranean room where you can hear the voices of people on other boats in the distance. The air is a comfortable seventy degrees at any time of the year (so bring a sweater or light jacket if you tend to get cold)." - Matt Barrett's blog (He's very enthusiastic about the Diros Caves)

In "deep Mani"(interactive map link) you will see the arid, rugged landscape of its reputation. The deserted village, Vathia, is where the famous tower houses remain standing.
This part of Greece was never completely occupied by the Ottoman Empire and the families (clans) that built these houses had a reputation of being tough like the landscape. You can read more about the whole region of Mani and check-out interactive maps at John Chapman's site, "Mani: A Guide and History".
*I would recommend staying at Gythio as a base and exploring the region from there by rental car. There are lots of quiet beaches you can discover following the coast of Mani and great seafood!