BOGOTA – A vibrant stream of giant murals greets people heading in from Bogota’s main airport or walking down the cobblestone streets of colonial downtown.

Stencils of pineapple-shaped grenades and AK-47 rifles arranged in a rainfall formation allude to Colombia’s violent politics. Monkeys and butterflies spray-painted in bright colours pay homage to the country’s natural beauty and provide welcome relief amid the Andean capital’s grey skies and monochromatic red brick architecture.

The proliferation of murals grew in part out of tragedy, when police shot and killed graffiti artist Diego Felipe Becerra in 2011 as he painted his trademark Felix the Cat. Bogota Mayor Gustavo Petro responded by decriminalizing graffiti painting and even offered several public buildings as canvases.

Street art has subsequently exploded across the city of 8 million. By one count, there are now more than 5,000 large paintings on walls or the sides of buildings, many now well-known to the tourists who sign up for guided graffiti tours on bicycle.

Canadian pop star Justin Bieber even got in on the graffiti action here, rushing after a 2013 concert with a police escort’s red lights flashing for the chance to scrawl on a wall.

Bogota’s laissez-faire attitude toward graffiti contrasts with that in many other Latin American cities. Buenos Aires, Argentina, last year raised penalties for street art, which it considers to be vandalism. In the Peruvian capital of Lima, the mayor this month had city workers cover up several murals by graffiti artists.

Major cultural institutions here are taking notice. The city-run Contemporary Art Museum held an exhibition this year highlighting the work of Bogota street artists who go by aliases such as Joems and the MonsTruacioN collective. The city also recently commissioned, at a cost of around $10,000, an eight-story-high depiction of the late Colombian novelist and Nobel laureate Gabriel Garcia Marquez.

“It’s a way to socially change the perspective of the city and give a present to people,” said Nicolas Castro, a 21-year-old artist working on the Garcia Marquez mural.

But even amid the freedom, some landmarks, including churches, national monuments and traffic signs, are off-limits.

“We hope that the graffiti continues, that it’s vibrant,” said Claritza Ruiz, Bogota’s secretary of culture. “But we also hope that young people come to recognize that not everything can have graffiti put on it.”