After more than seven decades of thrills and chills, the toboggan slides at the Forest Preserve's Swallow Cliff Woods in Palos Township soon will be just a memory.

Demolition starts this month, and Chicago-area residents are paying their last respects as the popular pastime fades into oblivion.

"This was monumental history that needed to be saved," said Maria Rogers, curator of the Palos Historical Society. "Once it is torn down, you can never put it back up."

It is too late to save the five slides known collectively as "Terror Hill." Rather than pay more than $1 million for renovations, Cook County Board commissioners in April approved demolition of the aging concrete structure.

Pan-Oceanic Engineering will dismantle the chutes from top to bottom for $54,400. Crews will start smashing the concrete foundation within the next three weeks, as soon as insurance and paperwork clear, said Gulzar Singh, the firm's president.

Bill Bush, a Palos Hills resident, said future generations will miss out on the excitement of the chutes.

"I've seen a lot of the kids come here just broken-hearted," he said. "It is a shame."

But economics have to trump sentimental feelings in this case, Cook County Forest Preserve District spokesman Steve Mayberry said.

"There is a feel-good part to it," he said, "but the fact is the facilities were run-down. It required a huge fiscal commitment that did not go hand in hand with the realities of running of the forest preserve."

In the last six years of operation, the toboggan runs were open 45 days at a cost of $2,500 per day, said Cook County Board Commissioner Elizabeth Doody Gordman, R-Hinsdale. The slides have been shuttered since 2004, she said.

Demolition plans do not include a hut perched atop the hill, which is being considered for a future concessions site. Pan-Oceanic also will reduce the hill's incline for future sledders.

Mayberry said he expects sledding dramatically will boost the use of the hill.

"You can't sled down a toboggan hill, but you can toboggan down a sledding hill," he said.