On one of our first days in Santa Marta, we decided to dig into the local culture. For a reasonable fee, a local guide agreed to show us a secluded swimming spot near Bahia Concha, the beach itself, and include a typical Colombian lunch with his family in a suburb of Santa Marta. The lunch might have been the most interesting part of the day. There were 11 people, including 6 kids, living in a 600 square foot, 3 room house, with concrete floors. They had electricity and running water, albeit they said it hadn’t been installed for their neighbourhood until 10 years ago. Very welcoming and friendly folks!
Here are a couple good posts for more info on Bahia Concha:
http://alittlecameo.com/2013/04/06/must-visit-beach-bahia-concha/#comment-1205
http://trotamunda.wordpress.com/2013/08/31/bahia-concha-shell-bay/