Cartagena is the author's favorite city in Colombia because it has both historical sites like its colonial architecture and modern buildings. Some popular tourist sites to visit include the walled city center, hotels and restaurants along the pond, the busy area of Bocagrande, and islands near Cartagena with white sand beaches. The city's cuisine features dishes like coconut rice, fish with plantains, seafood stews, crab rice, shrimp cocktail, and egg arepas.