La Seu (Cathedral of Santa Eulalia)

Towering above the center of the Barri Gòtic district is Barcelona's principal cathedral, La Seu. Considered one of the finest examples of Gothic architecture in all of Spain, the cathedral's construction began in the late 13th century, though it wasn't completed until the mid-15th century. Its ornate exterior depicts the lives of saints; intricate lace-like carvings flank the entrances. Inside La Seu, the main attraction is its 14th-century cloister overlooking a verdant tropical garden. While you're here, make sure to dedicate plenty of time to the numerous examples of artisanship that went into completing this cathedral, from the sprawling nave to the whimsical cloister.

According to recent travelers, December is one of the best times to visit La Seu, as the courtyard comes to life with local craftsmen selling homemade Christmas decorations. However, the pedestrian square in front of the cathedral — Plaça de la Seu — is always lively.

La Seu is open to visitors daily and entry to the cathedral is free, but you will have to shell out a few euros if you wish to explore places like the roof or the crypt. Visitors are also welcome to view the Sunday noon performance of the sardana, a Catalonian folk dance.