CARLSBAD, Calif. -- Thousands of guests at Legoland California will begin construction today on what's being billed as the tallest lego tower ever constructed.

More than 500,000 Lego bricks will make up the 90-foot tower when it is finished on Monday, according to Legoland California.

"When finished, this will be the tallest Lego structure in the world," said John Jakobsen, president and general manager of Legoland California.

If the tower doesn't topple, it will beat the existing record of 89.3 feet set last year at Legoland Billund in Denmark. That structure took some 50,000 guests four days, 32 hours to complete.