Riddarholm Church (Stockholm): Evoking pre-Reformation Sweden, this is one of the best-preserved Franciscan churches left in northern Europe. After being consecrated at the dawn of the 14th century, it served for centuries as the mausoleum for Swedish royalty. The church's cast-iron steeple, which dates from 1841, remains one of the most distinctive landmarks on the Stockholm skyline. The interior is especially impressive; coats of arms of knights of the Order of Seraphim, founded in 1336, cover the walls. The floor is paved with gravestones. After you visit the church, you can walk through Stockholm's Gamla Stan, or Old Town.

Uppsala Domkyrka (Uppsala): This twin-spired Gothic structure, nearly 120m (400 ft.) tall, was constructed in the 13th century. Today, the silhouette of this largest cathedral in Scandinavia dominates the landscape, affording Uppsala the status of ecclesiastical capital of Sweden. With a remarkably simple layout compared to other major European cathedrals, its high Gothic aura is nevertheless impressive. In one of the chapels on the south aisle, you can visit the tomb of the philosopher Emanuel Swedenborg (1688-1772).

Domkyrkan (Cathedral of Lund) (Lund): The apex of Romanesque architecture in Sweden, this imposing twin-towered gray sandstone cathedral is one of the most ancient in Sweden. It was consecrated in 1145, although actually launched sometime in the 1080s by King Canute II. Some of the sculptural details of its architecture evoke Lombardy or other parts of Italy. This is especially evident in its apse, which dates from the 1130s.

Vadstena Abbey (Vadstena): Sweden's greatest abbey is dedicated to its patron saint, St. Birgitta, who has brought lasting fame to this charming little town on the shores of Lake Vättern. In the Middle Ages, the abbey was at the center of a pilgrimage, which earned it the appellation of "Rome of the North." One of the most important stopovers for those taking the Göta Canal trip, Vadstena is dominated by its Klosterkyrkan, or Abbey Church, built between the mid-14th and 15th centuries to the specifications of its founder, St. Birgitta herself. This Gothic church is rich in art and relics from the Middle Ages.

Kiruna Kyrka (Kiruna): This church in the far north of Sweden in the midst of Lapland would hardly make it in the grand cathedral circuit of northern Europe. However, it is one of the most unusual churches in the world and causes a lot of raised eyebrows at first sight. It was constructed in 1912 like a stylized Sami tent, with an origami design of rafters and wood beams. In Lapland it is hailed as "the Shrine of the Nomadic people." A free-standing bell tower in front is supported by props and the tombstone of the founder of Kiruna. The only incongruous note is that the altarpiece has a scene representing Paradise as a Tuscan, not Lappish, landscape.