I've been to a lot of place on the face of the Earth - Victoria BC, the Greek Islands, the Big Island of Hawaii, the Rocky Mountains... this beat them all. Everywhere you look is like being inside a postcard. For the first time in my life I had altitude uneasiness - the train rides are 4 different trains that take over an hour going up. Bring sunglasses! Also bring warm clothes. At the uppermost outpost the wind was blowing so hard, you felt like you might be blown away - it was incredibly cold and almost scary and this was in May. I would advise going in May as everything is green in the valley going up to the mountains with all of the Swiss houses and barns of a similar architecture. Buy a half-pass if you are going to be in Switzerland for a week or so as this cuts the cost from a pretty steep 280 CHF (Swiss francs) to 1/2. This mountain is known as Jungfrau. We stayed in Winderswil which is a cheaper alternative to Interlaken or Grindewald.
If you own or manage Jungfrau, register now for free tools to enhance your listing, attract new reviews, and respond to reviewers.