• 7.2km, about two hours on a route rated easy, with 220m of elevation change
• One way, not a loop: ride the S10 up to Uetliberg, walk to Felsenegg, then take the cable car down to Adliswil
• Food at both ends, with Restaurant Hillz at Uetliberg station and Uto Kulm near the start, and the panorama Restaurant Felsenegg at the finish

A ridge walk from Uetliberg to Felsenegg that maps the solar system to scale: every meter of path stands for 1 million kilometers. Kids follow it from the Sun past the eight planets to dwarf planet Pluto.

At Felsenegg the view stretches over Lake Zurich to the Alps, and the IceAgeCam next to the restaurant gives an interactive look at the same view through the ice ages.