Cartagena

Enclosed within a protective wall reaching up to 20 m in width, the Ciudad Amurallada (or "Walled City") is Cartagena's old beating heart. Packed with well-preserved colonial buildings, it's a pleasure to stroll through; its streets of colourful low-rise merchant homes marked by iconic balconies are now mostly walked by either tourists or students who attend classes at the University of Cartagena during the day and linger for meals and nightlife after school is out. Cafes in Plaza Aduana and Plaza Santo Domingo teem with patrons, forging an incredibly jovial atmosphere; the districts of San Diego and El Centro are two not to be missed. There is plenty of food and shopping to be had, with a mixed bag of world-class restaurants and street food hawkers and the incredibly photogenic palenqueras — women dressed in vibrantly coloured clothing selling fruit in the streets — images of whom have become emblematic of Colombia as a travel destination.

A feat of Spanish colonial military architecture, the Castillo San Felipe de Barajas is one of Cartagena's most prized attractions. The fortress, whose construction finished in the late 18th century, was never seized – and not for a lack of attempted forays. Part of its sophisticated system of underground tunnels is open to the public; a guided tour (audio guides available) is highly recommended.

While seasoned travellers may venture into Cartagena's gritty Bazurto Market on their own, those not yet toughened by locals-only markets of the region may prefer to explore as part of a guided tour. This sprawling market, where trade starts before the crack of dawn, features incredibly fresh produce and seafood from Cartagena and beyond; much of it makes its way to the tables of local fine dining establishments within the space of the same day. There is plenty to look at and taste, including local street food and multiple succulent varieties of tropical fruit you're unlikely to have encountered before.

The buzzing Bairro Getsemani is, perhaps, Cartagena's most attractive neighbourhood, for both its well-preserved colonial architecture and vivid street life. Known as the nightlife hot spot of Cartagena, Getsemani stays up until late at night, with locals and visitors mingling in and around Plaza de la Trinidad over drinks and street food.

Just an hour's boat trip away from Cartagena lie the magnificent Rosario Islands, which belong to Colombia's only underwater natural park (the 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.

Housed in a beautifully restored Jesuit school building from 1612, the Museo Naval del Caribe covers in some detail the 500 years of Cartagena's maritime history. You'll find sunken ships, cannons, ship's bells, muskets, and other treasures here. The descriptions are in Spanish, so it's a good idea to get a guided tour.

The mangrove tunnels of nearby La Boquilla are an easy day trip from Cartagena. Guided tours will often combine a visit to the beach (one of the Playas De La Boquilla) with a boat or canoe tour of the mangroves, passing through Cienaga de Juan Polo and the Cienaga de la Virgen lagoons. Some tours will also include a closer encounter with local fishermen and offer insight into their craft. La Boquilla is an area of contrasts: the district of upscale hotels — Morros — borders on humble neighbourhoods populated by workers. When sitting down to tuck into no-frills seafood dishes served up by local eateries, make sure you're clear about the price of each item ordered from the get-go, as there have been reports of "surprise" bills amounting to several hundred US dollars.

If snorkelling and/or scuba diving sounds like your idea of fun, Cartagena is the place to indulge. Waters of the Caribbean washing over this part of the coast hold abundant marine life, including multiple varieties of tropical fish and corals, and the several underwater shipwreck sites make for exciting diving. The archipelagos of Rosario and San Bernardo are both excellent for either. Diving Planet Cartagena:

There is more than one way of exploring the beach: if you have had enough of sun tanning and frolicking in the surf, join a tour that puts you on a back of a horse. The ultimate romantic experience of riding along the sandy shore is available to riders of all levels. Feel like a character from a bodice ripper and get some spectacular photos for your Tinder profile while you're at it.

It would be a shame to be on the Caribbean coast and not take a boat ride out to sea. One of the best ways to enjoy a bit of naval activity and get ready for a fun night ahead is to take a romantic boat trip at sunset. The trips usually depart around 4:30 pm and give you a couple of hours under the sails. Enjoy magnificent views of the city skyline, with plenty of time to take photos in the golden hour, enjoy the snacks and drinks on offer, or just sit back and watch the sun dive into the Caribbean waters.