Planning a trip to Barcelona or Switzerland. Any advice?

I am a 21 year old student (US) and I'm planning on traveling with a friend of mine to either Barcelona or Switzerland (Near Interlaken) for a week. We are wondering if anyone has any tips to help us narrow down our choice.

Right now we are torn between the awesome scenery and nature of Switzerland vs. the culture/architecture/historical sites of Barcelona. My main concern with Switzerland is that there may not be much else to do other than hiking around the mountains.

Has anyone been to either of these places before and can lend some helpful advice?

Thanks in advance for any suggestions you guys have!