The Rock al Parque (Rock in the Park) festival in Bogota, the biggest free music fest in Latin America, turned 18 on Saturday in the Colombian capital and for three days will feature 17 international bands and dozens of local ones.

Santiago Trujillo, director of the Idartes art institute, told Efe that the first day “will be dedicated to classics of rock, heavy metal and hardcore, the second day will be for punk rock, reggae and some electronic inventions and the third will be all fusion music – rock-pop and rock-indie.”

According to the official, in Rock al Parque’s 18th year it has become an embedded part of the city “for fans of alternative and independent rock.”

On this occasion, Trujillo said, “We’ll have the daddy of rock in Spanish, Charly Garcia,” who will close the 2012 event next Monday onstage at Simon Bolivar Park on the Colombian capital’s west side.

Other crowd-pleasers are here from Spain like Siniestro Total, “a group that fashioned and fed the punk movement in Bogota and Medellin in the 1980s and has a big fan base here,” Trujillo said.

Also coming from Spain is Bigott, and from Costa Rica Las Robertas, among the dozens of bands on hand to excite the crowds.

Bogota authorities expect this year’s festival to draw between 260,000 and 300,000 fans.

This time, Trujillo said, as the festival “reaches adulthood” in its 18th year, it will be based on “diversity and the understanding that rock, alt and indie music have really taken off over the past few years.”

Besides the festival’s three separate stages, this year the festival will also feature an “ecotent,” a space for kids to learn from “projects that impart an understanding of the different rock cultures and how these rock cultures are related to the environment – urban architecture, zero trash, defense of animals and anti-bullfighting movements,” Trujillo said.

Besides the Spanish and Costa Rican groups, also taking the stage will be the U.S. hardcore band NOFX and the iconic Welsh heavy metal group Skindred.

As will Steel Pulse, a true headliner on the international scene, according to Trujillo, and other top groups from Colombia like 1280 Almas, Systema Solar and Ciegossordosmudos.

What is vital for Trujillo is to let the world know that this is “a meeting place for a diversity of aesthetics, views, sounds and colors that come together in Bogota,” adding that “it has always been understood that way by its fans, who have made it a paragon of harmony.”

The three stages and the ecotent are open for three days between the hours of 11:00 a.m and 11:00 p.m. local time.