The spread of youth gangs has accompanied the origin and development of large industrialized cities, starting with countries such as the United States of America. In recent decades, however, the phenomenon has undergone unprecedented expansion also in Europe and emerging countries as a result of the uncontrolled growth of urbanization; and it has taken on new transnational forms, thanks to the increased criminal mobility favoured by globalization.

Two are the main features that characterize gangs anywhere in the world. The first is the intense and essential relationship they have with the street, most notably in ghettos and slums: the gang as corner society. The second is marginality: gangs constitute an embryonic form of self-organization of a minority community cut off from the normal mechanism of social ascent. This contributes to explain why gangs have long been identified as a form of social deviance, if not of mere criminality. Today, although ethnic homogeneity within the single groups still prevails, ethnicity is rarely an immediate cause of conflict. Rather, turf wars often witness individuals belonging to the same ethnic group fighting against each other. Furthermore, some gangs have demonstrated their capacity to create settlements in countries (sometimes on continents) different from those of origin, giving rise to authentic phenomena of criminal colonization of the landing neighbourhoods.

Each gang follows its own specific path dependence: gangs born in particular places, they undergo their own life cycle, from latency to institutionalization, which can allow them to evolve from simple agglomerations to real transnational networks, as well as determine their decline. Gangs are also a phenomenon linked to the transition from adolescence to adulthood that can, therefore, reach exhaustion in the absence of an adequate generational turnover. Gangs’ affiliates are not doomed to live in crime. Rather, their fate depends on the strategies adopted by institutions to contrast the phenomenon and, to an even greater extent, on the criminogenic factors in a specific context. Gangs, in fact, are in all respects one of the forms assumed by the growing clustering of the criminal industry, in a market of illegal goods and services that gets more and more complex and global, and completely immune to the cyclical downturn in demand. Besides being an indicator of low integration and limited social cohesion, the diffusion of gangs in urban areas represents a manifestation of the existence of a criminal milieu so sophisticated to allow major groups (mafias and drug cartels) to implement risk externalization strategies, or the subcontracting to the gangs of tasks – street crimes – which involve more visibility and, consequently, greater likelihood of incurring in repressive action by the state.

As further confirmation of the importance of the organizational factor, gangs demonstrate an extraordinary capacity to increase intra-group cohesion through the creation of their own subcultures, capable of providing their affiliates with a system of beliefs and rules, as well as a vision of the world that are able to place them at the center of the universe and above others (not relegating them, for once, to the margins and bottoms of society). The tenets of these subcultures are: violence, chauvinism, and religion. Violence has a symbolic value, to the point of being adopted as an initiation ritual: inflicted on new recruits, or exercised by them to the detriment of uninvolved peers. Yet violence is above all an individual competence and an asset for the group: a professional duty that, if not fulfilled, can lead to mockery and derision or even expulsion and death; and that, for this very reason, must be accompanied by all the trappings of courage, reputation and honour. Furthermore, gangs serve also to satisfy the need for a (misunderstood) manliness incited by the culture of origin still imbued with patriarchalism and, on the other hand, denied by the host society, which prevents young people from becoming adults by taking on normal working and parental roles.

Paradoxical as it may seem, religion is the one single element that, in the majority of cases, provides gangs with that set of rules and principles required to ensure internal cohesion. An evidence of this is offered by the diffusion among the members of the gangs in different countries of religious tattoos, which cover all the declinations of Christianity: from the Catholic ones of the Neapolitan Barbudos, to the Protestant evangelical ones of the Central American maras, to the Orthodox ones of the Russian gangs. Tattoos – that are often associated with complex linguistic and gestural codes – satisfy the need to emphasize one’s own differences, the “we” from the “they”, and to strengthen loyalty to the group to the point of making it literally indelible. This also helps to explain why religion can then become a vehicle of redemption. This is demonstrated, for instance, by the case of Central America – one of the most violent regions in the world precisely because of the spread of the so-called maras – where Pentecostal evangelical churches manage to play a key role in providing teenagers with an alternative to gangs, using religious practices and group therapies to reintegrate them into society and to reframe their models of street masculinity.

How important gangs’ sub-cultural dimension is, is also demonstrated by the fact that street (and prison) gangs have been able to give rise to one of the most important phenomena of popular music of the twentieth century: the rap and hip-hop movement, which successfully got out of the ghetto, one could say, to become a mass phenomenon, a manifestation of counterculture and protest. Not only that. Born as a product of the black gangs of the United States, it has been declined over the last few decades in every slang and is now establishing itself as a propaganda tool of criminal brands, as for the Mara Salvatrucha 13 (MS-13) and the Eighteenth Street Gang (also known as Barrio 18), able to form their own groups of Hispanic rap and produce music videos, some of which now boast millions of followers on social media.

The above-mentioned examples are not accidental. MS-13 and Barrio 18 have become the paradigm of a new global threat. The first, in particular, has long been identified as the number one public enemy of the United States – where, for that matter, it was born, on the outskirts of Los Angeles, made up of young Salvadoran immigrants, in response to other Hispanic gangs who had long been rooted in those neighbourhoods. The massive deportation policies adopted by US administrations since the end of the decade-long civil war in El Salvador, has in fact allowed the MS-13 to carry out a “return” colonization, soon extended to much of Central America and, more recently, to Europe (Spain and Italy) and Australia.