We had a port of call there in March 2016. We did a private excursion with Dora the Explorer with two other couples from the ship. She was a great guide and we highly recommend her. Just google "Dora the Explorer Cartagena" and she will pop up - lots on Trip Advisor about her as well. We really enjoyed Cartagena - actually just saying the name is fun. Although you can DIY - if it is your first visit, I really recommend getting a tour - some of best sites are pretty spread out.