It all started with Madonna -- the original Madonna -- and the 16th-century Italian artists who paid tribute to her with chalk and pastel artwork they drew directly on the street. Madonnari, as the artists came to be called, made a living traveling from town to town and collecting coins from people who admired their work.
It was the visual arts equivalent of busking, and the tradition continued until World War II, when, for obvious reasons, it became impractical to sit in the middle of a street and create art.
After the war, the art of the Madonnari languished, but before it could die out completely, a group in the city of Curtatone, Italy, decided to revive it.
The first I Madonnari festival in Curtatone, in the province of Mantova (Mantua), was held in 1973, with some of the prewar Madonnari among the participating artists.
And that was the catalyst for a new generation of "street painters" who travel from city to city, and festival to festival, creating chalk artwork that hardly lasts longer than the handful of days required to make them.
Typically, a chalk art or "street painting" festival has separate categories for "copyists," who reproduce famous paintings; "free artists," who create original two-dimensional works; and 3-D artists, whose work may be realistic or fantastical. Many festivals also make room for children, teens and amateurs.
The wonder of these works of art is the way they materialize before the eyes of the onlookers.
"First, there was nothing," said Denise Kowal, founder of the Sarasota Chalk Festival, which will take place in November. "Now, there is this art. And you watched it happen."
In truth, the art does not spring into existence overnight. It is carefully planned by the artists, who arrive with preliminary sketches and paintings that they will turn into large-scale pieces.
Where they work is also carefully planned by the festival organizers, who provide them with precisely measured spaces in which to create their work. Even the pavement is a consideration, as every patch and crack makes a difference when the asphalt is your canvas.
"The quality of the street determines the clarity of detail in the work," Kowal said.
Here are some of the world's top chalk art festivals that prove where the sidewalk ends, the art begins.
Victoria International Chalk Art Festival, Victoria, British Columbia
September 14 and 15
Now in its second year, this festival was inspired by local chalk artist Ian Morris, who has plied his trade on Government Street in Victoria for more than a decade.
He will be joined by a roster of international artists including Dutch artist Leon Keer, renowned for his 3-D surrealist chalk art; California artists Lori Escalera and Joel Yau; Oregon artist Cathy Gallatin; and Toronto-based artist Jo Lalonde, better known as the "Chalk Chick."
Festival Bella Via, Monterrey, Mexico
October 11 to 13
Italy might have given birth to the Madonnari, but Mexico's tradition of street painting/chalk art is just as strong.
"Some people don't go to museums, so we make public spaces a place for creativity and art," said Rosy Loyola, the festival's director.
Equally important is the festival's commitment to fostering young artists.
Among standouts to watch for are Veronica Violeta González Garza, Carlos Enrique Robledo Moreno, Margarita Botello and Omar Saenz.
Parque Mirador Asta Bandera will be the venue when this festival celebrates its 10th anniversary this fall.
Sarasota Chalk Festival, Sarasota, Florida
November 13 to 18