Rather neglected until recently, Spanish military engineers now have been studied in detail revealing that the Habsburg and Bourbon kings, from small beginnings in the sixteenth century, sustained an exceptionally large number of military engineers in the 17th and 18th centuries – over 600 in Europe and over 100 in the New World. Trained in mathematics, surveying, architecture and cartography they built a limited number of great forts, usually to defend strategic ports like Havana, Santiago de Cuba, Portobelo, and Cartagena de Indias. However, fortification was hardly necessary in the major capitals far from coastlines so their greatest, most enduring, achievements lay in cartography, road and water engineering, town planning and architecture.