Tucked beneath Cologne’s City Hall, this underground site gives you a glimpse of the city’s Roman past. You can walk through the remains of the governor’s palace and parts of the old sewer system—surprisingly intact.

Scattered throughout the Old Town, these twelve churches are among the oldest buildings in Cologne—most of them date back to the 12th and 13th centuries. They’ve all got that heavy Romanesque look, but each one’s a bit different. Great St. Martin stands out with its massive tower right by the river, St. Gereon has got an unusual oval dome, and St. Maria im Kapitol is one of the largest. You don’t need to see all twelve, but stopping in at a couple while you’re exploring the Old Town gives you a good feel for the city’s medieval side.

At the northern end of Largo do Senado you can find this superb 16th century Baroque church said to be the most beautiful in Macau. Make sure not to miss the small museum in the back that collects around 300 artefacts dated from 17th to 19th century.

Built from the late 14th to the 15th centuries, the Santiago Cathedral is the city’s oldest major church, dedicated to Saint James (Santiago), Bilbao's patron saint. The building features a mix of different styles: its core is Gothic (nave, vault, cloister), a grand Renaissance portico was added in the 1500s, while much of the façade and tower with spire were rebuilt in a neo-Gothic style in the late 1800s by Severino de Achúcarro. Inside, you’ll see three naves, several side chapels, the Gothic cloister accessible via the Door of the Angel ('Puerta del Ángel'), and beyond the main altar, there’s an ambulatory with chapels. Floods in 1983 caused damage, but the cathedral was restored and reopened around 2000.