Porto's history is stacked vertically: a Roman river port called Portus Cale, a 12th-century fortress-cathedral on the hilltop, a 14th-century wall, and the Liberal siege that scarred the whole city. Three days walking that chronology, uphill.
Begun c.1110 as a fortified church — note the crenellated roofline and rose window. João I married Philippa of Lancaster here in 1387, sealing the Anglo-Portuguese alliance. Cloister azulejos by Valentim de Almeida, 1729. Open 09:00-18:30.
The surviving stretch of Porto's 14th-century wall, built 1368-1437 under Dom Fernando to enclose a city that had outgrown the Romanesque Sé. Once 3km with 18 gates; this granite curtain above the Douro is the best-preserved run.
Gothic shell of 1383 filled with roughly 300kg of gilded talha dourada carved 1725-1750 — the Tree of Jesse pillar is the masterpiece. Below, the 18th-century ossuary holds Franciscan bones behind a glass floor panel.
The warren below the cathedral is the surviving medieval fabric of Portus Cale — one-room-wide houses stacked five storeys on granite, alleys too narrow for carts. Slated for demolition in the 1960s, saved by the CRUARB rehabilitation plan.
Built 1842-1910 by the Commercial Association on the ruins of the São Francisco convent, burned in the 1832 siege. The Arabian Hall took 18 years and 20kg of gold leaf; the Pátio das Nações honours Porto's 19th-century trading partners.
Nicolau Nasoni's 75m baroque tower, finished 1763, was Portugal's tallest building for a century and the navigational landmark for ships entering the Douro bar. 240 granite steps spiral to the bell chamber.
Housed in a 1930s mansion used by the PIDE secret police until 1974. Displays cover the Liberal Wars, the Peninsular campaign and Portugal's African wars, plus one of Europe's larger miniature-soldier collections. Closed Mondays.
The 1795 palace served as Marshal Soult's French headquarters in 1809, then Wellington's the same year after he crossed the Douro by wine barge and routed the garrison mid-lunch. Portugal's first national museum, founded 1833.
Traditionally Henry the Navigator's 1394 birthplace and Porto's medieval customs house. Excavations under the courtyard exposed Roman mosaics and walls from a 4th-century domus — the physical proof of Portus Cale. Closed Mondays.
A 1416 Gothic convent church whose interior was buried in gilded carving in the 1730s. It sits directly against the Fernandine wall, and the adjoining courtyard preserves masonry from the older 13th-century Cerca Velha circuit.
Beneath the Brotherhood's 1750 oval church lie burial galleries where members were interred until the 19th century; glass floor sections reveal the loculi. The Christus collection upstairs holds 16th-19th-century religious silver.
Gustave Eiffel's 1877 Maria Pia railway arch was the world's longest single span at 160m; his partner Théophile Seyrig answered with the double-deck Luís I in 1886. Both replaced pontoon crossings, one of which collapsed in 1809 drowning hundreds.