In 1998 we took a vacation to Santa Marta, which is a Caribbean destination on the north coast of Colombia. Though Santa Marta was founded in 1525, earlier than nearby Cartagena (1533), it doesn't have the colonial character of Cartagena but has other attractions, particularly its coast, which is influenced by nearby mountains. To the east of Santa Marta is Parque Tayrona, one of Colombia's national parks, which has areas of natural and archaeological interest.
The main beach area is south and west of Santa Marta proper, in an area called El Rodadero, which has most of the tourist-oriented amenities and hotels. Further west and removed from the El Rodadero area is the Hotel Irotama. It faces a nice beach and also has this beautiful swimming pool.
See my webpage on Colombia at http://www.latinandcaribbeantravel.com/colombia.html