This volume brings together eight essays that address the result of a research project involving a group of international scholars. It explores a little-discussed, yet interesting phenomenon in the Caribbean and Gulf of Mexico region – how military engineers reshaped the physical landscape for imperial reasons and, in doing so, laid the foundations for broader colonial development. Moreover, this transnational scenario reveals how military construction reached beyond cross-borders themes and histories from the age of imperialism. As such, this book provides valuable insights into the role of military engineers in the process of articulating new American countries from the late 18th to 19th century. While this time period is full of international and local conflicts, it remains essential for understanding the region’s history – from the Gulf of Mexico to the Caribbean Sea – and even its current situation. Due to independence movements and Spain’s Decree of Free Trade (1778), the region’s connection with Europe changed dramatically. This affected the entire American continent, but had a particularly peculiar in the Caribbean and the Gulf of Mexico. For this reason, this volume underlines the key role of military engineers on other fields, from railroad design to environmental intervention, through cartographical works, and in diplomacy, all the while overcoming the traditional perspective of military engineers as being only builders of structures for war.