LOS ANGELES -- Rock stars are a common enough sight in Los Angeles, but it's not often when a rock is the star.

Los Angeles residents have been coming out to catch a glimpse of a massive boulder that arrived at the Los Angeles County Museum of Art before dawn Saturday, after lumbering across Southern California for the past week and a half.

It will become the centerpiece of acclaimed earth artist Michael Heizer's latest creation, "Levitated Mass."

"The sheer size of it is just impressive. The size of the rock, and the size of the undertaking," said Ron Dickson, 64, who drove down from Burbank.

The 340-ton hunk of granite, accompanied by an entourage of about 100 people, left a dusty quarry in Riverside on Feb. 28, chauffeured toward its destination by a specially built carrier as long as a football field.

The convoy made it to Wilshire Boulevard at around 4 a.m. Saturday, with hundreds of people looking on and museum officials updating its progress on Twitter. In its final mile, the moving crew paused to pose for photos in front of LACMA's "Urban Light" exhibit, before turning north on Fairfax Avenue, then east on West Sixth Street to its permanent home on the museum's north lawn.

At the museum, the rock is to be placed over a 465-foot-long trench, where Heizer has promised that visitors who walk underneath will experience the illusion that it is floating above them.

The artist, noted for mammoth-scale works in which the earth itself becomes his palette, is perhaps best known for "City," a Mount Rushmore-sized creation he has been building near his home in the Nevada desert for decades. He has kept most people from seeing it, but photos that have surfaced show a number of huge, pyramidlike buildings, some as high as 80 feet, stretching across more than a mile of desert terrain.

He came up with the idea for "Levitated Mass" more than 40 years ago, then spent decades searching for the right rock to pull it together.

He finally found one six years ago in the two-story high, 340-ton megalith he located in Riverside, 60 miles from the museum.

Because of the rock's size it took museum officials months just to work out an acceptable route to take it on. They finally settled on a roundabout journey that carried it through 22 Southern California cities.

Elizabeth Kuder, an artist and admirer of Heizer's work, strolled over from her house a few blocks away to snap photos of the site. Kuder said she believes the journey itself was part of Heizer's vision, pointing out how from some angles the rock appeared to defy gravity even while on the truck.

"It seems that "levitated mass" began the moment they were able to lift the boulder off the ground," she said. "It was levitating above the streets as it traveled. It was something to see."

The project, anticipated to cost as much as $10 million, is being funded by well-heeled museum donors.

With the rock finally in place, museum officials hope it will be ready to be unveiled sometime in the late spring or early summer.