LOS ANGELES (Reuters) - It weighs 340 tons, stands 21 feet, 10 inches high and measures 32 feet across. Beyond its massive size, this granite boulder being delivered to Los Angeles is no ordinary rock. It is art, or will be soon.

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Last week, the huge rock embarked on an 11-day journey from the California desert to its new home at the Los Angeles County Museum of Art where it will become the centerpiece of artist Michael Heizer’s “Levitated Mass.” He conceived of the artwork in 1968, but only discovered the right boulder six years ago while scouring a granite quarry.

It is expected to arrive in the early morning hours on Saturday and will take weeks to put in place before the installation opens to the public in late spring or early summer.

When “Levitating Mass” is completed, people will walk into a sort of trench in the ground underneath it, and the boulder will seem to rise in the air and hover above their heads. The museum hopes the work will become a major attraction for tourists and others at the museum.

But getting it to Los Angeles hasn’t been easy. In fact, transporting the boulder has been an epic undertaking that curator Michael Govan has compared to the building of the great pyramids.

For the past year, workers have been wrangling the monolith onto a 294-foot-long trailer with a combined weight of 1.2 million pounds -- a load as wide as three highway lanes.

Originally scheduled for an August 2011 move, bureaucratic tangles held it up for six months as government permits to travel through four counties and 22 cities created a nightmare of negotiations and paperwork.

“A lot of it’s in the route planning, traffic lights, electrical signals, those kind of things,” CHP’s Officer Daniel Hesser told Reuters. “And at times they are actually moved out of the way so that the load can go through.”

“You hope the roads can accommodate it,” cautioned Hesser. “They’ll check bridges and those types of things to make sure everything moves as safe as possible.”

In preparation for its journey, the boulder was shrink-wrapped and strung with 800 feet of lights for visibility during its nighttime move.

The 106-mile journey, beginning in the Jurupa Mountains east of Los Angeles, has been undertaken outside peak traffic hours to alleviate road congestion. Leading the procession is a 600-horsepower tractor pulling the load with another 600-horsepower tractor pushing from behind.

During the day, the boulder has rested in the middle of the road, closing traffic routes to commuters. Averaging seven miles per hour, it has taken a circuitous route to the city.

Once it arrives, the rock will be placed atop a 456-long trench in the ground where it will keep with Heizer’s notion of ‘negative-space’ wherein a landscape’s absence is emphasized.

In the case of “Levitated Mass,” the trench is combined with an epic presence, the boulder, to make an indelible impression upon visitors to the museum.

Total $10 million cost to move the boulder was paid for by the museum through private donors. Many have wondered how it could justify such costs during difficult times, but museum director Michael Govan sees it as a boon to the local economy.

“You couldn’t ask for a better gift to the economy right now than to be paying iron workers, truck drivers, concrete, construction workers,” said Govan. “It makes sense in our modern California culture to take advantage of the outdoors for monumental sculpture because people love it.”