If you want to party, then Cartagena is the spot, and you will have no issues finding a club/lounge in Cartagena, but that comes with a price. Prostitution is legal in Cartagena (I have no opinion on that), so you will see more women out in the streets once midnight hits in Cartagena. This leads to some uncomfortable situations if you do not how to proceed as a man. First and foremost, do not dance with someone that you think might be a prostitute, as I was told by a local (I speak Spanish and am Latino) that they even ask for money just by dancing with you. I laughed this off, but I noticed some ladies were pretty clingy if they felt they can get something out of you. It's not a huge deal if you know how to proceed, but proceed with caution. All that being said, Colombians love to party and they played a mix of hip-hop, salsa, and reggaeton while I was there. Also, I walked back by myself to the hostel at 2AM. You will see some shady people, but I never felt unsafe. Enjoy!