Nyon, a small Swiss city on the northern shore of Lac Leman, is only 20 minutes by train from Geneva central station. It is connected to Yvoire (where I spent some good time and you see photos of the village here, here and here) by a regular boat service. In fact, the port with small boats and the castle with five round towers atop the hill are dominating the skyline and are recognizable even from Yvoire, lying across the lake on the French side.
Nyon castle is a short walk up the hill from the port. The area in between is the city centre with lakefront walkways, souvenir shops and restaurants. The castle was built in 13th century and has five distinct towers. Besides the castle, there is an old church and old marketplace with a statue of Cesar. Three Corinthian columns stand in a corner of a small park offering beautiful view of the lake.