Colombia is known for their gorgeous emeralds and the jewelry they make with the stone. This museum shows how they are mined and how they were discovered. The museum is free and leads into a jewelry store where you can buy jewelry if you wish!
Take a day trip easily to Volcan de Totumo! It's now inactive and full of mud where people go to get a mud massage :) Very touristy but cool day trip experience. Can go with group or solo. Before 9am is better if you want to avoid crowds, about 1 hr away.
Giant modern mall in old town Cartagena! It was built on the oldest stadium in the city and they have light shows every night. Many cool stores and restaurants in this giant mall. Worth checking out!