The present research entitled "The Architecture of War" by Evangelia Dourakis and supervised by Mr. Georgios Mitroulias, follows the historical review of the events and situations. The importance of architectural design in every war operation is evident through the parallel and interrelated co-operation with the strategy of war. The science of architecture has always responded to every circumstance of siege, invaders, hostilities as it happened in prehistoric times and in antiquity, designing precincts and walled cities and organized fortified lines of defense, while in the internal turmoil during the 19th century in Paris, urban planning forms a new city with open streets and monumental buildings. At the same time, the discovery of gunpowder and the development of the cannon changed the tactics of attacks and developed new systems of fortifications. The strategic planning of wars which concerns the objective of the military and political leaders, has a direct influence on the architectural design and formation of the terrain, settlements, cities and buildings as well as the campaign camps during the Roman years. While the war spreads and occupies the third dimension of space, the technological development of weapons and the strategy of bombing cities, moves life underground and organizes it in shelters. Likewise, the defense is promoted outside the city with the need to organize the ground necessary for the fighters, who are protected on the ground and fight through it. War is a social phenomenon affecting the organization of city-states, defense is part of planning. Over the years where everything changes and evolves rapidly (society, politics, economy, technology), war becomes widespread and architecture finds its place with the modern methods it uses.