Sanctum within the Santa Maria del Mar Church in Barcelona (©Trey Ratcliff/Flickr/Creative Commons)
Looming above the streets in the hip neighborhood of El Born, this church is a prime example of 14th-century Catalan Gothic architecture. It boasts a soaring central nave and flat-topped octagonal towers, and a simple interior burned by locals in 1936 during the Spanish Civil War. Regular concerts are held here. Open Mon-Sat 9am-1.30pm, 4.30pm-8pm; Sun 10.30am-1.30pm & 4.30pm-8pm.