If we look at the course of history, at the past of certain events, we have probably thought: "never again". "Never again" such a level of destruction after the atomic bombs on Hiroshima and Nagasaki, "never again" let ourselves be divided by separations, especially ideological ones, like those that gave birth to the Berlin Wall.
Why, then, has the policy of building walls continued to grow steadily over the last thirty years? Will this security complex be able to withstand the future challenges of the international system?
1. Unfulfilled hopes
Walter Benjamin, in his manuscript On the Concept of History, notes: 'The astonishment that the things we experience are still possible in the twentieth century is not philosophical. It does not lie at the beginning of any knowledge except this: that the idea of history from which it derives is not sustainable'.
The fall of the Berlin Wall and the end of the Cold War deeply marked the popular imagination: the end of a world divided into two spheres of influence, separated by conflicts and border disputes had finally been realised. The fall of the wall and the emergence of a new international system that would lead us towards globalisation seemed to doom the concepts of 'state' and 'borders' irrevocably.
The present, however, seems to suggest that these hopes and expectations have been dashed. From 1989 to 2010, in fact, forty-eight new walls were built in the world.
Erecting a wall for defence purposes is probably the oldest instrument and symbol of security invented by man: the walls of Troy, Babylon, the Great Wall of China or Hadrian's Wall.
Barriers created to define the borders of a state, mark the political and cultural differences between different ethnic groups, defend against the enemy's desire to conquer. Moreover, the wall has had and continues to have a precise characteristic: while on the one hand it has the function of dividing from an 'enemy', on the other hand it serves to unite the population that wants to defend itself, creating an identity. By marking a boundary with those who are recognised as 'different' and therefore fearsome, one can also try to eliminate the natural internal divisions of a people.
Unlike in the past, however, in the present each state controls its own territory, which has precise borders, regulated by international law, which the other countries in the world have recognised and decided to respect. The majority of the world's states are members of the United Nations and have signed its Charter, which recognises the territorial sovereignty of each of its members.
What then is the task of a wall in the present time?
In the last thirty years, in the era of globalisation, the purpose of building a wall has become precisely that of blocking, or at least reducing the movement of unauthorised civilians and unregulated goods and services. In the second half of the twent