La Guaira’s urban character was slowly being defined throughout the seventeenth century, and in the late eigh-teenth century reached the compact appearance of a fortified city. The history of La Guaira fortifications is linked to the port’s defensive system, which by the late eighteenth century had 20 structures, including castles, forts, batteries and bastions. The fort of El Principe or Zamuro, known as «El Vigía», originally has a crescent shape and a watchtower. Strategically located over «El Colorado» battery and with an impressive view of the bay, it was orde-red built by Governor Francisco de Alberro in the late seventeenth century. This defensive building, which marks the beginning of the Way of the Spaniards towards Caracas, was known for the presence of a watchman who an-nounced the arrival of ships in port, by waving flags and ringing bells. Its structure is based on an outer fortifica-tion consisting of two half bastions called a «hornwork» in order to strengthen a weak flank, a crescent or semicir-cular tower, and a fortified base or watchtower with sentry boxes on the corners. Under the main platform is an inner vaulted space that was used as a jail. After World War II, this important monument was built up for mili-tary activities, with constructions that altered the hill’s profile and invaded the fort.