12 Fortified Port Cities Where History Meets the Ocean Waves

4. Cartagena, Colombia: Guardian of Caribbean Gold

A crown jewel of the Spanish Main, Cartagena’s extensive fortifications were vital for protecting treasure fleets laden with New World gold from pirates and rival empires. Completed over two centuries, its defenses include the formidable Castillo San Felipe de Barajas, a masterpiece of military engineering with a complex system of interconnected tunnels. The city's colorful colonial streets are cocooned within nearly 11 kilometers of robust walls, a vibrant reminder of its strategic importance and tumultuous, swashbuckling past on the Caribbean coast.