LAS VEGAS » Developers are announcing plans to build a 33-acre open-air music venue on the Las Vegas Strip to host a four-day Rock in Rio USA festival beginning next year.

MGM Resorts International said Monday that the City of Rock development to be built between the Circus Circus resort and Sahara Avenue could attract up to 80,000 people a day.

Rock in Rio began in 1985 in Brazil, where 600,000 tickets for the event last September sold out in four hours, according to organizers. Headliners included Justin Timberlake, Beyonce, Metallica and Bruce Spring­steen. The organization also produces festivals in Portugal and Spain.

Rock in Rio founder Roberto Medina says he’s excited to partner with MGM Resorts, Cirque du Soleil and Cali­for­nia developer Ron Burkle on the U.S. venue.

Plans will need county approval, and cost figures haven’t been made public.

Officials say they’re planning five stages; themed streets featuring sights, sounds and foods of Brazil, the U.S. and the United Kingdom; plus thrill rides and shopping.

The event will be separate from the three-night Electric Daisy Carnival electronic music festival, held in June at the Las Vegas Motor Speedway.