Cartagena, San Agustin

Colombia has a lot to offer depending on what you want to see & do. From a quick glance at your profile, it seems like you like to explore in the outdoors rather than cities, but I’d spend a few days in the capital, Bogota, to check out the Gold Museum, the National Museum, La Candelaria, Monserrate, etc. and the sourroundings (Zipaquira, Guatavita). Villa de Leyva in Boyaca (a few hours from Bogota) is one of my favorite places. Medellin or Cali won’t require as much time as Bogota, but they’re still unique & interesting. Cartagena has a lot of touristy places (Ciudad Vieja, Castillo de San Felipe) and is closer to Santa Marta & Tayrona National Park, where Ciudad Perdida is located.

There’s so many different unique regions, climates & geographies that it really depends on what you want to see: there’s the Caribbean, the Andean & coffee-growing region (highlights are the Coffee Museum & Nevado del Ruiz near Manizales, and Nevado del Tolima), the Pacific Coast offers a great contrast of rainforest & beaches (Gorgona National Park) and has great scuba-diving (Malpelo) as does the Caribbean region (San Andres & Providencia, and Islas del Rosario near Cartagena). And though I never had the chance to make my way down, the southern tip is in the Amazon, bordering with Brazil, and I’ve heard good things about Nariño in the southwest bordering with Ecuador.

Hope that helps! Have a great trip! :)

The previous comment, couldn´t describe it better, Colombia is a country of regions and this are very different between them.
Bogotá itself is so a magical place, La Candelaria is an historical place with a lot of nice restaurants and colonial houses, i recommend you don’t miss a typical Santafereño breakfast (Tamal, chocolate with bread or Caldo de Costilla)in La Puerta Falsa a nice restaurant very famous in La Candelaria if u ask for it, everybody can tell u where it is.
In Cartagena and Santa Marta try the Arepa de huevo which is a special fried cake with an egg inside!! sounds crazy but delicious! also taste patacones and the caballitos, you can find them in “El Portal de los Dulces”, in the Plaza de los Coches in Cartagena and also enjoy the wild nights of fiesta that this cities offer you!!
Islas del Rosario is one of the most common places to go close to Cartagena but there is another islands that could be of your interest like Isla Múcura, not too touristic like Islas del Rosario but still unique and beautiful.
La Guajira, another place in the caribbean region, is a desert in the caribbeann, pretty far away so Cartagena and Santa Marta but also interesting especially El cabo de la Vela.
There are a lot of places to go and a lot of different foods to enjoy.
One last recommendation!! take care with your stuffs if u miss something probably nobody give them back to u… sad but true!! anyway enjoy your trip Colombia is an awesome country!!