From the 13th century, the Counts of Savoy began building a mighty castle on top of Roman ruins, dominated by five huge towers. Nowadays this castle, towering over the Old Town, houses the Museum of History and Porcelain, containing valuable items from the former porcelain manufacturing industry in Nyon. From the 16th century onwards, the town was ruled by Berne, and a reminder of this can be seen in the arcades around the market square.
Three Corinthian columns on a little hill in the parkland by the lake recall the Roman era. After Julius Caesar had conquered Gaul, he decided to establish the colony of Iulia Equestris with Noviodunum as its urban centre on the site of the present town of Nyon, as shown by the artefacts from excavations on display in the Roman Museum.
The Museum of Lake Geneva in the district by the lakeside tells you all about Western Europe's largest lake. There are aquariums, large and small models of boats and a restored steamer to tell the story of the natural history and shipping of the lake. Higher than this district, a promenade offers fine views of the lake, Geneva's nearest mountain - the Mont-Salève - and Mont Blanc.
Nyon is surrounded by vineyards. The Route du Vignoble de la Côte from Versoix near Geneva through Nyon to Morges is all about the wines of La Côte and other regional specialities. Local fish from the lake are served with the wines, complementing them perfectly. A little railway line leads into the hinterland of the region, going as far as the Jura resort of Saint-Cergue and the French border in La Cure.
A special place of interest is the Toblerone Trail, which has nothing to do with the famous triangular chocolate, but rather the anti-tank defences, similar in shape, forming the "Promenthouse Line" which stretched from the foot of the Jura to Lake Geneva. Signposts along the footpath help give you a good impression of what the fortifications of the Second World War were like and also point out a number of unspoilt natural features.
- Old Town – arcades similar to those in Berne and a castle with five round towers, dating partly from the 13th century.
- Museum of Lake Geneva – information about the origins of the lake, its fauna and flora and the history of shipping, fishing etc. With a children's workshop.
- Prangins Castle – just a few kilometres outside Nyon there is a section of the Swiss National Museum housed here. In this very attractive setting, under the title "The Way to the Present", the history of Switzerland in the 18th and 19th century is unfolded.
- Arboretum in Aubonne – in the valley of the Aubonne in 1963 the canton of Vaud established Switzerland's first arboretum, where there are 3000 indigenous and imported species of tree to be seen.
- La Garenne zoo in Le Vaud – a glimpse into the European animal world, with wolves, lynx, foxes, reptiles and a large number of European birds of prey in attractive grounds.
- La Dôle (1677 m) - a mighty, rocky crag above Nyon, with almost alpine vegetation and a panorama over Lake Geneva, the city of Geneva and the Alps of the Valais, extending as far as Mont Blanc.
- The Vaud Jura Park - 75 km2 of sunlit forest and meadow landscape of national importance, with good viewpoints. Information centre in St-George.
- Tintin in Nyon – with the help of a mini-guide, retrace the thrilling journey that Tintin and Captain Haddock made through Nyon on the trail of Professor Calculus.
- Easter – during Easter week the fountains in the Old Town of Nyon are extravagantly decorated, with a competition for the general public (March).
- Nyon International Archaeological Film Festival – films which bring the many aspects of archaeology closer to the general public (held every two years in March, e.g. 2007).
- Documentary Film Festival "Visions du Réel" in Nyon – a platform for experimental works and a meeting place for artists working on the general theme of "Reality" (April).
- Paléo Festival – Switzerland's largest open-air festival, all different styles of music with music from around the world, a combination of festival and party, attracting nearly 200,000 visitors annually (July).
- Festival of the Performing Arts – theatre, dance and music in theatre auditoriums and on the streets (August).
- Michel Sogny Festival – an excellent small piano festival in the castle of Coppet (August).
- Festival of Traditional Jazz in Cheserex – for more than 30 years this festival in this little village near Nyon has concentrated on traditional jazz (November).