Matt Cardy via Getty Images BRISTOL, ENGLAND - JULY 27: People walk past artwork produced as part of the 2016 Upfest on July 27, 2016 in Bristol, England. The annual event, which this year helped celebrate 45 years of the Mr Men and Little Miss book series, started in 2008 and is said to be the largest free street art and graffiti festival in Europe. The festival now attracts more than 300 artists including Inkie, Jody, Pichi & Avo and Leon Keer from 25 countries to paint live on walls and surfaces around Bedminster and Southville areas of the city of Bristol, the hometown of guerrilla artist Banksy. Some of the graffiti art work is painted on moveable boards and temporary hoardings, but murals on some venues and buildings remain all year until the next festival. (Photo by Matt Cardy/Getty Images)

In the opening scenes of the Netflix series The Get Down, New York subway trains stumble across an overpass with opening credits spray-painted across their carriage side. It's the perfect set-up for the remarkable convergence of anti-war, racial tension and economic disparity that was New York City circa the 1970s. Today we are at a similar crossroads where issues of immigration, inequality and social intolerance are in danger of dividing our cities once again.

Of course, graffiti is not a modern creation. As far back as ancient Africa graffiti was a common form of communication, depicting stories of love, war, religion, literature, art and commerce. From rocks and boulders to rudimentary stone walls, every surface was a billboard to make a statement. The authors of these works were the storytellers of the times. Today, in the British Museum, Royal Ontario Museum, and numerous other institutions around the world, relics of this time inform how we understand early city life.

So is graffiti street art, social platform or simply a criminal act?

Banksy, the mysterious artist uses graffiti to make timely social, environmental and political statements on topics such as the BP oil spill and Middle East tensions. Considered an important artist, the fact that his work often disappears so quickly can also be seen a reflection of our disposable, high-speed times. The late artist Keith Haring first used subway carriages as his canvas to depict the sexual awakening and AIDS crisis of the early 1980s that created fear as it swept through New York City. As Banksy himself has said, "Graffiti is one of the few tools you have if you have almost nothing."

The hip-hop community adopted graffiti as a form of social expression to speak about the urban issues of the day -- police brutality, lack of jobs, poor housing, drugs and street crime. This was expressed in music too, but the raw vitality of graffiti meant you didn't have to buy the music to get the message. Graffiti signatures, or tags, became integral to identifying gangs, crews and groups that helped mostly young, urban communities connect with each other.

Since the U.K. and Europe woke from the shocking Brexit result, there has been a notable rise in hate crime with overtly homophobic statements sprayed on surfaces in London, Cardiff and Middlesborough, among others. Elsewhere across a divided Europe graffiti is once again the weapon of choice for those expressing social and political opinion.

There is a "broken window" theory that says small acts of violence, such as graffiti, lead to greater civil disruption and crime. New York City led the way on this as police policy changed in the 1990's. More recently however, this has been tempered as reports show other social factors may have played as much of a role in reducing crime over that time. It might be convenient to say that a visible crime such as graffiti must be stopped before our cities unravel, but the reality is that it is more often a costly diversion of limited law enforcement resources.

While some city officials continue to crack down on graffiti in public and private spaces, with fines of up to $10,000 or ironically, community service, this creative outlet gives voice to residents and enriches our understanding of the very real issues facing growing cities.

Here in Toronto, Graffiti Alley, a laneway system that runs behind downtown city shops, has even become a favourite of teachers, with groups of students strolling among the colourfully sprayed tags, enjoying the artwork but also learning about the power of free expression.

Graffiti has also been adopted by business in an attempt to connect with urban youth. Toyota, McDonalds and Coca Cola have all launched product campaigns that depict street graffiti, associating their product with hip, urban life. More recently, Heineken took the urban connection a step further, launching a city restoration project that celebrates the graffiti filled walls of Miami Marine Stadium with a crowdsourcing campaign to restore the stadium to its former glory as a live music venue. This campaign intrinsically links graffiti to urbanism, communicating the mix of despair and hope of community-led building at its best.

Like London's Speakers Corner, graffiti gives voice to citizens who might not otherwise be heard. Their authors are city dwellers discussing critical, urban issues. What they have to say may not always be appreciated, and you may not agree with it, and certainly this is not to condone racist, defamatory remarks, but cities are places of high tension. It's a part of what makes them the vital, exciting places that much of the world population are drawn to live in. This tension needs a release valve and I don't know about you, but I'd rather take graffiti than the more violent, disruptive alternatives.

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