Central Greece is the part of the mainland between Thessaly and Epirus in the north and Attica and the Peloponnese in the south. Delphi and Ossios Loukas are UNESCO World Heritage Sites. Mountains such as Parnassus and Giona have hiking routes, and Parnassus has a ski centre. The Achelous and Sperchios rivers cross the region, Messolonghi lies beside a lagoon, and Evia is a large island off the east coast.