Switzerland is hikers paradise. One of the most amazing hikes i ever did was the two day tour over the Greina plateau. It lays on 2300 meter over sealevel between the two cantons Graubünden and Ticino. You can enter the greina from various sites. We have started in Vrin/Puzzatsch in the canton of Graubünden which you can easily reach by public transport. The ascent is quite steep but it can be done in two houres and once you are on the plateau it's not exhausting anymore. Still wear good hiking shoes, it's saver and much more fun if you can reach more exponated places. We for example climbed trough a steep rockfield and reached an amazing, unnamed lake which i am sure has not been reached by many people this summer. Bring a detailed map for things like this. It looks quite difficult to get lost in the plateau but still it is in the middle of the alps and you would not be the first to get lost there.
The whole plateau is maybe 5 km long and has several valley arms. Every part of the Greina looks different so it's always amazing looking around the next corner. Sometimes it's realy stony and grey, then it turns to a powerfull green again. Trough the middle flows a small river with little turquoise pools. There are three SAC (Swiss Alpine Club) Huts on the plateau (Capanna Motterascio, Capanna Scaletta, Terrihütte SAC- www.terrihuette.ch) where you can spend the night (70.- CHF including dinner and breakfast). Call in advance that they know that you are comming. Camping is not allowed on the whole plateu. We only spend one night up there but if you have time it's absolutely no waste to stay two nights.
To get down we took the way behind the Terrihütte. You have a great view but it is realy steep and i was glad to go down. I would definitely not recomend this way for going up :) Once you left the steep part behind you follow the river until you reach a small artificial lake. The river is full of natural pools - perfectly for a swimm. At the artificial lake you can take a bus that brings you to the closest trainstation. Check out times in advance (www.sbb.ch), the place is called "Runcahez Val Sumvitg" and the last bus leaves somthing like about four o'clock.