The Marly Planet Path is described on My Switzerland.com:
"Take a walk through our solar system? Thanks to the planet path in Marly, you can do just that! The path begins at the sun, which has a diameter of 1 metre. The path runs alongside the Gerine river and passes through beautiful countryside all the way to the observatory (approximately 5 km away), where you will find the most distant planets, Neptune and Pluto. This informative outing can be combined with a visit to the observatory." Travel and contact information are updated there.