The Aletsch Glacier is the biggest glacier in the Alps, and you will ride your Mtb beside him for a very long time during the day.
I think it's one of the most extraordinary spectacles in nature I never saw in my life.
Thanks to the cabin you will reach the starting point very comfortably. The track starts from the green point in North direction. You will get toward a tunnel and then you will be almost in front of the glacier. A nice trail lead you in a super panoramic spot...prepare your camera. Same portage and you will be on the trail beside the glacier.
Enjoy it...1 hour and the trail start coming back at the starting point (green bubble).
Again on the original path till the tunnel, get over the tunnel, take the right and the downhill starts. The trail is sometimes aggressive sametimes flow and very long till the car.