After the tricked out palaces of Sintra, the shell of Castelo de São Jorge – or St. George’s Castle – is a bit of an architectural come down. (Although it must be noted that this former fortress has borne witness to the entire sweep of Portuguese history: from the Iron Age through to the Phoenicians, Romans, and Moors.) Occupying the highest hill in the city, the views from the citadel survey the wide expanse of Lisbon, as you’d expect. That alone makes it worth the climb. That and the peacocks.