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.

This splendid Midcentury modern white marble mosque can accommodate 5,000 worshippers and is reportedly the largest single-domed mosque in the world. Bear in mind that visits may only be arranged by prior appointment and are restricted to male visitors.

Rome is home to many astonishing churches that boggle the mind, such as the Mausoleum of St Costanza. Tucked away outside the Aurelian Walls, this 4th-century church is an example of early Christian art and architecture. Its mosaics of natural elements, such as birds, palms, and plants, along with the dome and the unusual design, make it the perfect setting for couples to exchange their wedding vows.