Two teen-age boys were seriously injured Tuesday afternoon when they fell several hundred feet in a restricted area of Stone Mountain Park, police said.

A third, who is 12 years old, was uninjured.

The father of the 12-year-old brought the teens — one 17 and one 18 — along for a hike on the mountain.

The father didn’t notice the warning signs and wandered past them into the restricted area.

“One of the kids saw this pipe (or culvert) and decided to go down it for some reason,” said Stone Mountain Park spokesman John Bankhead.

The teen “started to slide and couldn’t stop. The second, older kid went after him, and that’s when the problems started with those two,” Bankhead said.

On Tuesday, when he realized the two older boys were injured, the dad went for help. He instructed his preteen son to wait where he was.

“He was trapped in an area that was too tall for him to climb up, and it was slippery on both sides,” DeKalb County Fire and Rescue Deputy Chief Norman Augustin told The Atlanta Journal-Constitution.

Help was dispatched shortly after 12:30 p.m. to pluck the two youths from a ravine and help their uninjured, 12-year-old companion to safety.

The 18-year-old was flown by helicopter to Atlanta Medical Center in serious condition with head injuries, DeKalb County Fire and Rescue officials said. The 17-year-old was taken to Gwinnett Medical Center with a possible fractured ankle, authorities said.

DeKalb fire officials used a high-angle rope system to reach the injured youth in the ravine and pull them to safety in a rescue basket.

“We were fortunate that the patients were not critical and not profusely bleeding so we were able to take our time to set the rope system up,” Augustin said.

Then they went for the 12-year-old.

“He froze,” Bankhead said. “He was in shock. EMT’s got there and told him to stay there because he needed to rescue the two who were injured.”

Augustin said because areas of the rock were wet, DeKalb rescuers were slipping and sliding as they went to help the boy.

By 2:40 p.m., the rescue was complete. It took place near the Bird Sanctuary trail, on the back side of the mountain, away from the sculpture of Confederate Civil War icons.

No charges are being filed, Bankhead said, and none of the victims have been identified.

Gale Swanson knew all too well what the two teens were experiencing Tuesday. It happened to her 20 years ago.

“I fell off Stone Mountain on Jan. 1, 1993, and remember so well the horror of sliding and not being able to do anything about it,” she said in an email to The Atlanta Journal-Constitution.

“My feet slid out from under me,” she said. “I rolled over to try to grab onto something. But it’s hard to grab onto granite.”

Swanson landed on her right side, fracturing her pelvis in five places and breaking bones in her shoulder and ankle.