Jewel of the town is the massive St Ursen Kathedrale, an Italianate vision in local grey-white stone that seems to float above the main Hauptgasse. It’s crowned by a greenish tower which rises to 62m. (Incongruously, the steps leading up to the entrance are a favourite smoking spot for the local kids – not all the fragrant odours drifting about are ecclesiastical incense.) Overhead, the Latin inscription in gold running around the building refers to Solothurn’s patron saints, Ursus and Victor, who refused to worship Roman gods and were martyred. The bright, soaring interior (daily 8am–noon & 2–7pm; Oct–Easter until 6pm) is reminiscent of a wedding cake, with a riot of intricate stucco covering the white stone walls that is typical of the lavish late-Baroque era in which the church was built (1762–73).

Barely 100m along Hauptgasse is the atmospheric Jesuit church, sandwiched between shop-fronts – push the unremarkable door to gain entry to the extremely remarkable interior, dating from the 1680s and encrusted with a dizzying amount of lacy stuccowork. Halfway along Hauptgasse, overlooking the central Marktplatz, is the Zytglogge, Solothurn’s oldest building, the lower part dating from the twelfth century, the upper part from 1467, and the astronomical device in the centre from 1545. The hour hand on the giant clock face is longer than the minute hand.

A few steps north of the cathedral is the doughty Altes Zeughaus (Old Arsenal), housing a moderately interesting museum of militaria (May–Oct Tues–Sun 10am–noon & 2–5pm; Nov–April Tues–Fri 2–5pm, Sat & Sun 10am–noon & 2–5pm; Fr.6; SMP). This massive collection documents Solothurn’s history of battles and booty, most impressively with a gigantic hall full of suits of armour and more swords than you could shake a stick at. Some 50m east is the Baseltor, an old city gate dating from 1508. Hug the walls north to the corner bastion of the Old Town and you’ll come to the circular Riedholz tower, now the location of a summer cycle of prestigious classical concerts.

Across the lawns to the north lies the impressive Kunstmuseum (Tues–Sat 10am–noon & 2–5pm, Thurs until 9pm, Sun 10am–5pm; free). Highlights of this surprisingly good collection are Holbein’s Solothurner Madonna (1522), on a panel backed by the gorgeous Madonna in the Strawberries (1425), painted by the anonymous Master of the Garden of Paradise. Some spectacular Alpine canvases are led by Ferdinand Hodler’s awesome and much-reproduced portrait of a Herculean William Tell emerging from a break in the clouds. One of Hodler’s famous sequences of larger-than-life moving bodies decorates the stairs, while Klimt’s luscious Goldfish is another highlight.

Last but not least, way on the other side of town, on the southern bank near the Romandie landing stage, is the highly odd Krummer Turm, or Twisted Tower, a fortification of the town dating from the 1460s. Looked at from any point other than its axis of symmetry, it appears to be hopelessly lopsided; in fact, though, its base is an irregular pentagon (due to the tower’s original location at the sharp corner of a bastion of entrenchments). The spire on its scalene-pentagonal roof, although it seems about to topple off any minute, has been safe and secure these past five centuries. From the tower, you can cross to the northern bank and hike the riverside road for two hours west to the stork colony at Altreu.