Just an hour's boat trip away from Cartagena lie the magnificent Rosario Islands, which belong to Colombia's only underwater natural park (Rosario and San Bernardo Corals National Natural Park). Abundant marine wildlife (including over 50 species of corals) and some of Colombia's best beaches draw in many in search of relaxation and active pursuits such as snorkelling and diving. Isla Grande is best for kayaking through unique mangrove forests and seeing the phosphorescent plankton light up the waters of a brackish lake at night, while Playa Blanca is Cartagena's most spectacular white-sand beach (also reachable by land). It should be said that the company you choose to tour with has the potential to make or break the experience. Low cost tours can mean multiple intermediate stops en route to your destination, as well as unpleasant surprises such as no transfer back to your hotel. Try and choose a trusted company with consistently good reviews, or opt for a private tour. Mind that seas may be rough at certain times of the year, particularly in December and January, when tours on smaller boats may even become dangerous.

Relatively newly discovered by native villagers, the cave is extensive and unaltered, full of narrow, maze-like passages, and countless stalagmites. It is not advised to go without a guide, a crash helmet and a flashlight. The entrance is accessible only by boat and the whole trip would take approximately 2 hours. Near the exit of the cave, there is a mud bath onsen. However, given that the cave is not fully explored, the absence of certain security measurement exists. Thus going in alone is not recommended especially after 16h.

This is not just a park, but a representative scenic area covers more than 120 hectares. The park contains rivers, mountains, Chinese gardens, traditional architectures and an underground cave. The Seven Star Cave in the park is a fantastic karst cave with a large number of stalagmites and stalactites, which transform the cave into a surreal place. If you can only visit one place in Guilin, this should be it.