Cartagena, Colombia (pronounced "Carta hena") is both a port of departure and a port-of-call on Columbia's North-Central coast. It is a rather large city, with a population of almost 1 million people. The entire country of Columbia is on the US State Department's Travel Advisory list. However, if you stay in the tourist areas, they are relatively safe. Still, you need to be on-gard here as in any Caribbean port. The cruise ship will provide you an advisory of what taxis to take should you want to go on your own. And if you go by taxi, note that the rates are variable, and negotiate a price before you enter the taxi, or you could be looking at a $100 fee for going to the old city or downtown shopping districts.
The street vendors are rather pushy in this city, even to the point of banging on the side of tour buses attempting to sell their wares.
If you do not wish to venture into the town, there is a small shopping area adjacent to the cruise dock that has a few shops, a Parrot Emporium, and free Wi-Fi.