Café del Mar sits on the Baluarte de Santo Domingo section of Cartagena's colonial walls, looking out over the Caribbean. The position is spectacular — you're drinking cocktails on a 17th-century fortification while the sun sets over the water — and the place has traded on this for decades. It gets very busy, service is slow, and prices are high by Colombian standards, but no other bar in the city has quite this combination of location and atmosphere.
Arrive at least 30 minutes before sunset to get a decent spot. The cocktail list is extensive and the mojitos are good. Food is available but secondary. It's more a destination than a restaurant, and the experience is really about that hour when the light turns gold over the Caribbean and the walls glow amber.