Don't touch the Elvis "Trilogy." Or "The Devil Went Down to Georgia." Or the Confederate figures riding off the mountain carving. Heck, for that matter, don't mess with anything.

When it came time to revamp the Stone Mountain Laser Show —- the most popular attraction at the state's most popular park —- there was much that could not be revamped, lest the public outcry reverberate louder than the 65,000-watt sound system.

"We were very conscious of the sacred cows," said Stan Morrell, the show's creative director.

Change is tricky for the laser show, which celebrates its 25th anniversary this year (the park itself has its 50th anniversary). Saturday night marks the debut of a new —- and yes, changed —- show, the first of about 100 that will run through October.

The show's custodians want to keep it fresh and give audiences new surprises, but they know they run the risk of alienating regulars if they depart too far from familiarity —- plenty of patriotism, Southern pride, Ray Charles singing "Georgia on My Mind" and a big finale of fireworks.

"We're very cautious of what we put on the rock," said Gerald Rakestraw, the park's general manager and an Atlanta native who saw his first laser show when he was in high school.

Park officials estimate 20 million people have seen the laser show in its 25 years, and it's more closely identified with the state park than anything else it does.

"It's appealing to a certain audience, and they're sticking with that audience," said Cliff Kuhn, a history professor at Georgia State University.

"I can understand why they wouldn't want to try something a little edgy."

On summer nights, anywhere from 8,000 to 20,000 people gather on the huge grassy lawn that slopes toward the Confederate carving on the mountain. Towers of speakers —- new this year, with better sound —- play pre-show pop and country tunes while families spread out blankets and set up folding chairs, oil up with insect repellent, and wait for dusk to edge into dark.

The laser show is best-known for its "American Trilogy" section: Elvis Presley singing a medley of "Dixie," the African-American spiritual "All My Trials" and "Battle Hymn of the Republic," while the lasers and image projectors show aspects of the Civil War on the mountain's side. The lasers trace the outlines of Robert E. Lee, Jefferson Davis and Thomas "Stonewall" Jackson carved into the mountainside, animating them and making them appear to ride their horses.

"Trilogy" has been in the show every year since it debuted in 1983. The park briefly considered dropping it during the mid-'90s run-up to the Atlanta Olympics because of controversy over the use of "Dixie" and an image of the Confederate battle flag. But hundreds of outraged phone calls swept that notion off the table quickly.

"It's never gonna be 100 percent popular across all the races," said creative director Morrell. "But it is what it is."

Said GSU historian Kuhn: "I can understand that no matter what kind of changing political sensibilities there might be, why they would be loath to change too much."

"Trilogy" is staying, but the show's biggest switch is dropping its long-standing finale, Lee Greenwood's version of "God Bless the U.S.A.," which has been the finale since the '80s.

"I expect some e-mails —- 'Oh, it was so good, put it back in the show,' " said Morrell.

"I don't want to offend anyone, but how can you argue? I replaced it with the national anthem," which had not previously been part of the show.

The new finale, sung by gospel star Sandi Patty, becomes an extravaganza of patriotism and pyrotechnics.

Other changes that will be officially debuted Saturday night:

> A new overture starts the show —- the pounding timpani and dramatic horn fanfare of "Also Sprach Zarathustra," better known as the theme from "2001: A Space Odyssey."

> The regional section has several new country songs like "Loud" by Big & Rich, which means "Georgia on My Mind" has been shortened.

> Songs from Disney's "High School Musical" have been added for kid appeal.

> The show is a little shorter: 36 minutes, down from 40 last year. It has expanded and contracted slightly through the years as songs were added and eliminated.

> "We've tripled the pyro," said Morrell, referring to the fireworks and the flame cannons at the base of the mountain.

STONE MOUNTAIN PARK 25TH ANNIVERSARY LASER SHOW

Opens 9:30 p.m. Saturday. Also 9:30 p.m. May 10 and 17, May 24-Aug. 10, Aug. 16, 23, 30 and 31, and Sept. 1; 8:30 p.m. Sept. 6, 13, 20, 27; 8 p.m. Oct. 4, 11, 18, 25. Show is free, but admission to the park is $8 per car. www.stonemountainpark.com.

ON AJC.COM

Check out Wonders of Stone Mountain in an interactive map that highlights the park's natural and entertainment attractions.