After a ten-year hiatus, the world's largest music festival, Rock in Rio, returned to its hometown Rio de Janeiro for seven days of concerts from Friday, attracting 700,000 people over the whole week.

It is the 10th edition of the Rock in Rio festival, but only the 4th to be held in Rio as the organizers exported the fest to Lisbon and Madrid ten years ago. The first edition of the fest was in 1985, gathering an audience of 1.38 million in ten days of concerts, and the most recent edition in Rio was held in January 2001.

A total of 700,000 tickets were sold out for this year's festival. The success prompted organizers to announce an extra day of concerts, and tickets for that day has been sold out as well.

The festival consists of four stages, in which the concerts are expected to last up to 14 hours a day, with the participation of International stars including Elton John, Katy Perry, Shakira, Rihanna, and bands Metallica, Evanescence, and System of a Down.

Several stars which performed in previous editions of the fest, such as Guns N' Roses and Red Hot Chili Peppers, are also on the list this year. In addition, a number of local singers and bands, such as Paralamas do Sucesso and Titas, will also join this year.

The performance site, named as Rock City, is a 150,000-square-meter area. Besides the concert area, the site also has a giant Ferris wheel, a roller coaster, and a small shopping mall. After the fest, the Rock City area will be converted into a leisure area to athletes in the 2016 Olympic and Paralympic Games in Rio de Janeiro.

According to Rio's tourism company Riotur, out of the 700,000 people expected in the festival, some 315,000 will be tourists, who raised the hotels' occupation rate to 98 percent.

Riotur estimated that the Rock in Rio festival will generate 419 million U.S. dollars for the city and create 10,000 jobs.

The creator of the festival, Brazilian businessmen Roberto Medina, insisted on opening the Rock City gates himself, in the early afternoon, and greeted the first fans to enter the site.

"We come to the gate because the Brazilian audience is even more important than the bands. We applaud them. They make the greatest show," he said.