After Christopher Columbus launched his second and fourth voyages to the New World from Cádiz, the city began receiving treasures collected during the Age of Exploration. The prosperity of Cádiz grew exponentially. By the early 18th century, the Port of Cádiz managed 75% of the trade with the Americas. All that wealth attracted the greedy. The city was raided by Sir Frances Drake in 1587. Then the English destroyed Cádiz in 1596. In desperation, King Phillip II commissioned Cristóbal de Rojas to design an impenetrable defense. Within 25 years, the city was encircled by a curtainwall with intermittent guard towers and bastions armed with cannons. Castillo de Santa Catalina was also finished. Two bulwarks were added in the north part of town in the late 17th century. The construction of Castillo de San Sebastián followed in 1706. This exhaustive plan worked. The English attacked five times during the 17th and 18th centuries. As part of the Napoleonic Wars, the French assaulted Cádiz for two and a half years from 1810 until 1812. Each onslaught was successfully repelled. Most of these defenses are now yours to explore and enjoy.