Blausee is one of the best known Swiss mountain lakes, despite its small size. The name which simply means blue lake is a reference to its unique blue colour, which it has because of the special reflection in the crystal clear water. Blausee nature park is very popular for day trips in summer. There are walking trails, two restaurants, barbecue areas and a playground for kids. And you can cruise the lake with a glass-bottom boat. From Zurich, get there by train and bus in around two hours (change train in Bern and then take the bus in Frutigen).