Within the boundaries of America's natural wonderlands, few hiking paths are girded with handrails, most cliffs remain uncordoned by safety ropes, and the wild animals, though large and imposing, lumber free of protective cages.
For millions of visitors who come to national parks, the primary attraction, after all, is their undeniable wildness, which sets them apart from the typical neighborhood greensward.
But following a tragic incident at Yellowstone last month, in which a college student died and two of her friends were seriously injured after they wandered into a hot spring, danger in national parks has earned a higher public profile.
More and more, officials say, average tourists arriving in the country's premier nature sanctuaries are unprepared for what can happen when they leave the confines of their cars.
"When you go into the wilderness, you look at the peace and tranquility and don't expect the dangers, although you should ... because they are there," says Bob Reid of the Park Service's national law-enforcement training center in Glynco, Ga.
Weekend explorers, accustomed to city parks as nonthreatening places, are increasingly stumbling into trouble when they are not mindful of nature. So today, federal officials in Yellowstone and other national parks are searching for new ways - from flyers to videos - to educate visitors about the dangers of the American outback.
Statistics gathered in 1999 show that search-and-rescue operations saved 1,343 visitors and employees in national parks, 300 more than the year before.
From slippery waterfalls to untamed animals, each park makes its own demands on caution and good judgment, but Yellowstone presents park rangers with a suite of unique challenges.
For example, thousands of travelers converge along the famous Firehole River here to safely experience the novelty of sitting in a stream warmed by hot water - the equivalent of a natural outdoor jacuzzi.
But the river flows through a basin of geysers, hot springs, and fumeroles that are seething hot. The three college students, who had spent the summer working in Yellowstone, fell into Cavern Spring while they were walking to their dormitory from Firehole River at night.
"It's an accident that has hit everyone who works in Yellowstone especially hard," says Marsha Karle, a park spokeswoman. "These were three great young people who didn't do anything wrong or illegal, except make a simple bad decision...."
The park tries to avoid such mistakes by requiring its legion of young summer workers to attend an orientation session highlighting a litany of dangers.
And it is attempting to pass more of that advice along to visitors, too.
Park rangers hand out a leaflet at the park gate that specifically warns visitors not to get too close to rangy bison. And a dramatic video with a message along the same theme is shown at many of the Yellowstone visitor centers.
"A lot of times, people go into the parks and don't check with the rangers to see what kinds of hazards there might be," says Mr. Reid. "I know of some cases where lives were saved because the tourists bothered to ask a simple question, such as, 'What do I do when a bear attacks?' "
Researchers are also looking back into park records to see patterns of problems. Yellowstone volunteers Jim and Edna Caslick examined injury reports in the park involving wildlife going back 36 years.
Perhaps surprisingly, they found that far more people are hurt by bison in Yellowstone than by the park's famous population of bruins. Most injuries were to amateur photographers who got too close.
Despite incidents like those and the one at Cavern Spring, park officials don't think the answer is to fence off nature. Yellowstone wouldn't be Yellowstone if the effects of a litigious society forced park officials to make its attractions so tame that they cease to possess their primordial allure.
Says Ms. Karle: "We don't want a tragedy like this to force us into having signs posted at every hot pool or result in closing areas to the public."
(c) Copyright 2000. The Christian Science Publishing Society