Starting at Rue du Château 1, 2000 Neuchâtel, open the Explorial app and enter the 6-digit game code that you received by text and Viator chat message. You're at the foot of the castle hill in a city that has been administering western Switzerland since the 11th century. Your first landmark is the Château de Neuchâtel, the medieval castle and collegiate church complex whose towers and golden sandstone walls rise above the old town — the seat of Neuchâtel's counts and a remarkably well-preserved example of medieval Swiss architecture. From there the app takes you along Une rue fantastique, the 'fantastic street' — a celebrated example of architectural eclecticism where buildings from different periods and styles line up in a sequence that has been described as the most varied streetscape in Switzerland. The route concludes at the Quai Ostervald, the lakeside promenade where the full panorama of Lac de Neuchâtel opens up before you, with the Jura mountains on the far shore and the Alps visible on clear days beyond. Around 2 hours on foot. Neuchâtel's old town is compact and the lake always at the end of a downhill walk.