This trail is a good option if you want to hike down from the Riffelsee lake to Zermatt, instead of riding the Gornergrat mountain train.
Trail: moderate • 3h • 7.1 km • 950m descent • trail map
After passing the Riffelsee lake, the trail eventually forks left and descends on steep switchbacks to a valley formed by the Gorner glacier. A rushing river flows through the valley, a nice place for a rest and picnic.
The trail then leads to the Gletschergarten, which showcases some geological formations from the glacier times. As you continue down, you pass a nice picnic area with a playground. Then cross a long suspension bridge across the river gorge. Then through the forest, eventually arriving at the Furi gondola station.
From Furi, you can ride the gondola down to Zermatt.
Or you can keep hiking from Furi down to the Zermatt village, about 1 hour, passing through the Gorner Gorge attraction, with wooden walkways built on the side of the gorge's rock walls.
Other options
For a shorter, easier hike, you could hike from the Riffelsee to:
the Riffelberg train station (1 hour)
or to the Riffelalp train station (2 hours).