Torre dos Clérigos

The Clérigos Tower is Porto's exclamation mark — a 76-metre Baroque bell tower that dominates the skyline and has been the city's most recognisable landmark since it was completed in 1763. Climb the 240 steps of the narrow spiral staircase and you'll be rewarded with a 360-degree view that explains Porto's geography better than any map: the river curving west to the ocean, the terracotta rooftops cascading down to the Ribeira, the port wine lodges across the water in Gaia.

The tower was designed by Nicolau Nasoni, an Italian architect who essentially invented Porto's Baroque style. Nasoni was a painter who turned architect, and you can see the painter's eye in every detail — the tower narrows as it rises in a perspective trick that makes it appear taller than it is, and the ornamental stonework is as detailed as brushwork. He's buried in the church at the tower's base, which seems fitting for a man who defined the city's silhouette.

The climb is not for the claustrophobic — the staircase tightens near the top and the final section is essentially a vertical tunnel with worn stone steps — but the view from the gallery is worth the cardiovascular investment. Come just before sunset when the city turns gold, or at night when the tower is illuminated and the lights of Porto spread below like a circuit board. The church interior, with its Baroque altarpiece and Nasoni's painted ceiling, is free and often overlooked by visitors focused on the climb.