Colombia is a great place, the people are extremely warm and friendly. I've been here multiple times, having visited Bogota, Cali, and Medellin, and never felt threatened. That said, security is a serious issue in Colombia. This goes beyond the usual avoidance of the "bad side of town" that you would use anywhere. Travelling in Colombia is not the same as Western Europe or the US, even though those places can certainly pose risks as well. Various regions of Colombia remain seriously dangerous, both for visitors and residents alike, with kidnapping, political and narcotrafficing disappearances, etc... I have found that locals have an excellent sense for security, and are happy to provide advice. I like to birdwatch and was eagerly setting up a trip to a private reserve outside of Bogota, trying to line up a taxi driver who could take me there. My local friends immediately intervened and would let me proceed no further until they had looked into where this place was, and the security situation. It turned out to be fine after they looked into it, but the take home message is that a visitor is decidedly unwise to simply take off traipsing around the country with specifically investigating the security issues.