With the raise of tourism, local authorities have designated spaces for graffiti artists, yet some of them have claimed they were still chased by police.
Creating colorful pictures of surreal human faces, marine animals or even huge owls, hundreds of graffiti artists have turned the Chilean port of Valparaiso into a gigantic open-air art gallery.
Elias Street is typical of Valparaiso with its narrow sidewalks winding up and down Cerro Alegre hill, itself a tourist attraction.
There are many little streets like this that surround the 42 hills overlooking the Pacific Ocean that are a striking feature of the Valparaiso skyline.
Over the last few years, the walls of houses in Elias Street have been transformed into giant canvases where graffiti artists show off their skills.
It was brought about by "young people's need to go out and express themselves in the street," Sammy Espinoza, a graffiti artist and graphic designer, told AFP.
Only four years ago, two local university students, aged 18 and 25, were shot dead in Valparaiso, apparently killed by an irate householder as they sprayed graffiti on the wall of his building, media reported, citing police as saying the shooter had been arrested.
The incident provoked anger among student activists, who stage regular demonstrations that sometimes lead to clashes with the police, demanding better quality and cheaper education in Chile’s deeply unequal society.
Today, however, Valparaiso is one of Chile's most visited tourist sites, alongside the Atacama Desert in the north and Patagonia in the south.
There are almost 1,400 murals and graffiti artworks in the city and for the last five years they've found a place on the city's tourism circuit.
Hundreds of stairways, labyrinthine streets between the hills, cobbled alleyways and seemingly abandoned plots have converted Valparaiso, which lies 120 kilometers to the northwest of the capital Santiago, into "the perfect city" for creativity, added Espinoza.
That's why he and his partner Cynthia Aguilera, a civil engineer, left Santiago a decade ago to move to Valparaiso and dedicate themselves to graffiti.
They go by the name "Un Kolor Distinto" (a different color) and have created huge works of art such as "Solsticio de Verano" (summer solstice), a mural spanning all 22 floors of the Centenario building, one of the tallest in the city, with a surreal yellow face mixed with green and purple fruits and vegetables.
In 2003, UNESCO declared Valparaiso's historic center a World Heritage Site, recognizing what was one of the most important South American ports in the 19 and 20 centuries, as well as an improvised architecture that had to adapt to the city's hills.
Chilean artist Sammy Espinosa finishes a street mural in Valparaiso.
"There are those very beautiful wall drawings, everything mixes well, it's very beautiful," 31-year-old Italian tourist Alessandro Ferssini said as he took a tour of the city's graffiti circuit.
Every month, around a thousand tourists take that tour.
Some 300 graffiti artists, both Chileans and foreigners, have displayed their artwork on Valparaiso's walls during the last five years, according to 34-year-old Alvaro Ramirez, a graffiti artist and businessman.
"At first, most people looked at it as a scar on the city. 'How are you going to show the city's stains to the tourists?' they asked me," said Ramirez.
But now, "the people who come to Valparaiso, come for the colored houses, they see it as an artistic destination," added Ramirez, who started his graffiti in New York aged just seven, before returning to Chile at 21.
The locals have changed their minds about the graffiti artists they used to view as criminals.
Now they open their doors and allow the artists to decorate the walls of their homes.