All the steep whitewashed alleys through Skyros Town's historic core eventually lead to the Byzantine-Venetian fortress, which has been closed for restoration since a 2001 earthquake but may reopen. A marble lion, thought to be from a pre-existing acropolis, overlooks the kastro entrance, which gives way to the 10th-century Monastery of Agios Georgios (open to visitors).
On the way back down, pop in to tiny Agia Triada for its fine frescoes.