Bogota or Medellin?

[thrill_err]

I will be in Colombia for the first time this August. Flying in and out of Bogota. I'll be in Colombia for 8 days. I was wondering if its worth making a trip to Medellin or spend all 8 days in Bogota.
I cant speak spanish. I have made multiple trips to latin america (Mexico/Costa Rica/Belize).