Many visitors to the Peloponnese (Peloponisos, in Greek), only visit the Argolid, roughly the thumb of the three fingered 'hand' which this large peninsula resembles.
It is on this 'thumb' that are found the main Mycenaean sites of Mycenae and Tiryns, and the great theater of Epidaurus (part of the Sanctuary to Aslipios, god of healing), as well as the less visited Argive Heraion, also an important sanctuary.
The beautiful, elegant city of Nafplio/Nauplion is also an attraction for many, with its great fortresses and lovely neoclassical architecture. Approaches to this area are either by sea from the Argo-Saronic islands, or by land, most often via the road from Athens to Corinth.
The latter city is in the eponymous prefecture, visited mainly for the Corinth Canal and the remains of ancient Korinthos, though also for the sanctuary of Poseidon at ancient Isthmia near the canal, the spa resort of Loutraki north of the canal, Perahora ad Lake Vouliagmeni, and ancient Nemea.
The large prefecture of Lakonia in the south, which includes the two easternmost of the three 'fingers', is much visited for the fascinating Mani region and for the well preserved medieval Byzantine town of Monemvasia , high on its rock above the sea, as well as for the inland Byzantine town of Mystra, in a lush green area watered by the Evrotas River. The modern city of Sparti (Sparta) is nearby.
The large central prefecture of Arkadia offers lush valleys and beautiful medieval hill towns. The site of of the Temple of Apollo at Bassae (Vasses) is the most remote, and perhaps the most impressive sites in all Greece, though the restoration of the ruins here leave much to be desired.
Olympia (Olymbia in Greek), where the Olympic games were hosted for more than a millenium, is the main attraction for many visitors to the northwest prefecture of Ilia. In the northern province of Achaia is the large port of Patra, and in the mountains to the southeast, the village of Kalavryta, to which the famous rack and pinion railway runs from Diakofto on the coast, offering one of the most spectacular train rides in Greece.
Messinia prefecture in the south west includes the city of Kalamata, largest in the southern Peloponnese, and the twin Venetian fortresses of Koroni and Methoni, on either side of the westernmost 'finger' of the peninsula. The pretty town of Pylos sits on the landlocked Navarino Bay, near the ancient King Nestor ruled, and where the sea battle that effectively ended the four centuries of Ottoman rule took place (Battle of Navarino in 1827). The palace site of Nestor is surrounded by fertile valleys.