The sounds from guitars strumming and drums beating sears through the air. Crowds dance in circles while thumping their heads back and forth.

Some 38,000 fans attended Hammersonic this past weekend, according to organizers of Southeast Asia’s largest annual heavy metal music festival. Featuring 55 bands, the event is held in Jakarta, the capital of Indonesia, the world’s largest Muslim majority country.

One of the groups performing, Lamb of God, was barred from performing in neighboring Malaysia in 2013 after Islamic leaders there said some of the band’s songs were blasphemous. Interestingly, the current president of Indonesia, Joko Widodo, talks openly about his passion for heavy metal and says he’s a fan of Lamb of God.

“We’re a moderate Muslim country and that’s why we’re more open to foreign influence including heavy metal music than some more conservative countries” said Pri Ario Damar, dean of the performing arts faculty at the Jakarta Institute of Arts.

Damar, 49, was a bass guitarist in a local heavy metal band back in the 1990s and currently plays with his students from time to time. “Heavy metal has been popular here for decades,” he says. “So there are several generations of listeners here who appreciate it as an outlet to comment on society, politics and the environment.”

At 6 p.m. local time, during a break in the live performances at Hammersonic, many fans went to the designated prayer area. Some of them prayed wearing heavy metal t-shirts simultaneously showing their Muslim faith and favorite music.

While bands from around the world took the stage, Dian Ranidita, a 40-year-old Indonesian mother of three, tapped her feet to the rhythms while her husband Yanuardi gently bobbed his head up and down.

“The stereotype of heavy music is always dark, violent, aggressive and also like a devil, but actually heavy metal is not like that,” Dian said, adding that she’s been a heavy metal fan since high school because of the different themes in the music that she relates to.

“For instance, romantic themes when you have a broken heart or feeling like fall in love with someone. And also if you’re feeling depressed, there are also depression themes, and when you’re feeling like you want to release your adrenaline,” she said. “Those are some of the many themes in heavy metal.”

Sisi Selatan is a heavy metal band from the Indonesian city of Solo. The group performed songs about love and social activism while fans in front of the stage jumped up and down. Band members say Indonesia is a country that embraces foreign cultural influences.

“We [Indonesians] absorb foreign cultures,” said guitarist Adi Wibowo. “Not only metal music, but also Korean, Japanese, Indian music and more. We embrace these types of music.”

Denisa Dhaniswara is a 24-year-old heavy metal vocalist from Jakarta. Like many singers, she writes songs based on her own personal experiences in life.

“A lot of my lyrics are filled with grief and greed. So, I really want people to feel unsettled when you listen to my music,” she said. “It’s a way of saying: I’ve been feeling like this, do you relate? If you relate that’s good. I mean I’m not alone here.”

Dhaniswara says Indonesia’s heavy metal fanbase is growing as performers get better and better.

“Indonesia has a lot of newer heavy metal bands and that makes me very happy because we’re always emerging,” she said. “Always finding out new stuff. Everybody’s so creative.”