Fredrikstad was founded in 1567 as a marketplace at the mouth of the River Glomma. Gamlebyen (the Old Town) became a fortress in 1663 and continued in that role until 1903, boasting some 200 guns in its heyday. It still serves as a military camp and is the best-preserved fortress town in Scandinavia, but the moats and embankments make for an evocative walk.

The main guardroom and the old prison contain part of the Fredrikstad Museum, Tøihusgata 41 (tel. 69-95-85-00). At the southwestern end of Gamblebyen is a section of the museum in a former guardhouse from 1731. Inside is a model of the old town and a collection of artifacts, both civilian and military, collected by city fathers over a span of 300 years. It's open Tuesday to Sunday from 11am to 4pm; closed October to April. Admission is NOK40 ($8/£4) for adults, NOK20 ($4/£2) for children.

The cathedral of Fredrikstad, Fredrikstad Domskirke, Ferjestedsveien (tel. 69-30-02-80), was constructed in 1860 in a flamboyant Gothic Revival style. Its most notable features are its stained-glass windows by Emanuel Vigeland, the younger and lesser-known brother of Norway's most famous sculptor, Gustav Vigeland. The church was also decorated by other leading Norwegian artists. The Domkirke lies on the western bank of the Glomma and opens onto a small park. It is open Tuesday to Friday 11am to 3pm, and admission is free.

Outside the gates of the Old Town stands what remains of Kongsten Festning, the fortress of Fredrikstad, which was constructed on Gallows Hill and used by the townspeople as an execution site for criminals. When the Swedes took over the site in 1677, they fortified the stronghold with 20 cannons, underground chambers, passages, and a strong arsenal. Today you can scramble among the embankments, walls, stockades, and turrets. It is always open, charging no admission. To reach it, walk 15 minutes beyond the Gamlebyen drawbridge, turning off Tornesveien at the Fredrikstad Motell & Camping.

Bridge by Leonardo da Vinci

In Tuscany, Leonardo da Vinci drew the plans for a bridge in 1502. It was never built in his day. However, in 2001, da Vinci's stunningly modern pedestrian bridge opened in Norway, of all places.

The 99m (325-ft.) laminated timber bridge links Norway with its eastern neighbor, Sweden, at the town of Aas, a 26km (16-mile) drive south of Oslo. Many Oslovians, who have no real intention of going to Sweden, drive down to walk across this remarkable piece of Renaissance engineering.

Of course, da Vinci had a 216m (708-ft.) stone span in mind to cross the Golden Horn inlet at the mouth of the Bosporus between Peta and Istanbul. Sultan Bejazet II, at that time a patron of da Vinci, feared that it was impractical to build such a bridge. The plan died until the original da Vinci drawings were uncovered among some documents in the late 1950s.

Although only a scaled-down version of what da Vinci designed, it's a stunning bit of engineering, standing 8m (26 ft.) high at its pinnacle.

Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.