8 Best Sights in Catalonia, Valencia, and the Costa Blanca, Spain

At the heart of the Barri Vell, the cathedral looms above 90 steps and is famous for its nave—at 75 feet, the widest in the world and the epitome of the spatial ideal of Catalan Gothic architects. Since Charlemagne founded the original church in the 8th century, it has been through many fires and renovations.

Take in the rococo-era facade, "eloquent as organ music" and impressive flight of 17th-century stairs, which rises from its own plaça. Inside, three smaller naves were compressed into one gigantic hall by the famed architect Guillermo Bofill in 1416. The change was typical of Catalan Gothic "hall" churches, and it was done to facilitate preaching to crowds. Note the famous silver canopy, or baldaquí (baldachin). The oldest part of the cathedral is the 11th-century Romanesque Torre de Carlemany (Charlemagne Tower).

The cathedral's exquisite 12th-century cloister has an obvious affinity with the cloisters in the Roussillon area of France. Inside the Treasury there's a variety of precious objects. They include a 10th-century copy of Beatus's manuscript Commentary on the Apocalypse (illuminated in the dramatically primitive Mozarabic style), the Bible of Emperor Charles V, and the celebrated Tapís de la Creació (Tapestry of the Creation), considered by most experts to be the finest tapestry surviving from the Romanesque era.

Valencia's impressive 13th- to 15th-century cathedral is the heart of the old city. The building has three portals—Romanesque, Gothic, and rococo. Inside, Renaissance and baroque marble were removed to restore the original Gothic style, as is now the trend in Spanish churches. The Capilla del Santo Cáliz (Chapel of the Holy Chalice) displays a purple agate vessel purported to be the Holy Grail (Christ's cup at the Last Supper) and thought to have been brought to Spain in the 4th century. Behind the altar is the left arm of St. Vincent, martyred in Valencia in 304.

Stars of the cathedral museum are Goya's two famous paintings of St. Francis de Borja, Duke of Gandia. Left of the entrance is the octagonal tower El Miguelete, whose 207 steps you can climb (entry, €2): from the top, the roofs of the old town create a kaleidoscope of orange and brown terra-cotta, with the sea in the background.

One of Girona's most beloved churches and its first cathedral until the 10th century, Sant Feliu was repeatedly rebuilt and altered over four centuries and stands today as an amalgam of Romanesque columns, a Gothic nave, and a baroque facade. The vast bulk of this structure is landmarked by one of Girona's most distinctive belfries, topped by eight pinnacles. The basilica was founded over the tomb of St. Felix of Africa, a martyr under the Roman emperor Diocletian.

Constructed in a Gothic style over the city's main mosque between the 14th and 16th century, this is Alicante's oldest house of worship. The main door is flanked by beautiful baroque stonework by Juan Bautista Borja, and the interior highlights are the golden rococo high altar, a Gothic image in stone of St. Mary, and a sculpture of Sts. Juanes by Rodrigo de Osona.

Built between 1616 and 1662 on the site of a former mosque, this church (called a concatedral because it shares the seat of the bishopric with the Concatedral de Orihuela) has an austere facade designed by Agustín Bernardino, a disciple of the great Spanish architect Juan de Herrera. Inside, it's dominated by a dome nearly 150 feet high, a pretty cloister, and a lavish baroque side chapel, the Santísima Sacramento, with an elaborate sculptured stone dome of its own. Its name comes from the day that Alicante was reconquered (December 6, 1248) from the Moors, the feast day of San Nicolás.

This 12th-century Romanesque church is part of a 10th-century monastery, still in an excellent state of preservation. It's set on the town's main plaza, Sant Pere, with many cafés and terraces.

Founded in 977, this pre-Romanesque gem contains the relics of St. Vincent as well as the tomb of its benefactor, Pere de Rovira. La Capella de la Veracreu (Chapel of the True Cross) displays a reproduction of an alleged fragment of the True Cross brought from Rome by Bernat Tallafer in 977 and stolen in 1899.

A small plaza contains Valencia's oldest church (dating to the 13th century), once the parish of the Borgia Pope Calixtus III. The first portal you come to, with a tacked-on, rococo bas-relief of the Virgin Mary with cherubs, hints at what's inside: every inch of the originally Gothic church is covered with exuberant ornamentation.