English sea captain Sir Frances Drake assaulted and captured Cartagena de Indias in 1586. Immediately after paying “El Draque” (a ransom to leave), the Spanish vowed to fortify their city against future attacks. The initial coral walls, designed by Bautista Antonelli, were finished in 1608. About a half dozen watch towers still face the Caribbean Sea like this one called Baluarte de San Diego. It required 210 years to complete the fortification. The wall measures about 6.8 miles around the historic district.