For those who see the national parks as being preserved time immemorial under gigantic bell jars, there is evidence that each succeeding generation makes an imprint or two on the parks. It wasn't too terribly long ago, for instance, that you climbed into the bleachers to watch the bear buffets in Yellowstone National Park, or that the El Tovar Hotel at the Grand Canyon National Park had separate dining areas for men and women.

Hard as it is to believe, things do change in national parks. For instance:

* There was a time when some parks were racially segregated.

* Before snowmobiles tooled across Yellowstone, there were snowplanes.

* Where tourists used to hunt for logo-bearing ashtrays, rubber tomahawks, and even snow globes in park gift shops, today they're more likely searching for locally crafted artworks. (But I'd be happy with your circa-1960s snow globe!)

* You used to be able to find a payphone in national parks.

“Every new generation of park visitors interprets the National Park Service Act and implements new policies and services that are a reflection of the ideals of the times,” says Dave Hartvigsen, vice president of sales and marketing for concessioner Xanterra Parks & Resorts. “Some park decisions may seem a bit unusual to the current generation, but they were perfectly reasonable at the time.”

In 1932, three years before Shenandoah National Park was officially designated, National Park Service leaders were discussing the need to provide segregated facilities in the parks. In 1936, the Park Service's official policy on the question of blacks and whites at Shenandoah stated:

The program of development of facilities... for the accommodation and convenience of the visiting public contemplates... separate facilities for white and colored people to the extent only as is necessary to conform with the generally accepted customs long established in Virginia.... To render the most satisfactory service to white and colored visitors it is generally recognized that separate rest rooms, cabin colonies and picnic ground facilities should be provided.

In 1945, a federal mandate ordered the desegregation of all National Parks. It wasn't until 1950, however, that Shenandoah's facility's were fully integrated.

Perhaps it's no coincidence that Yellowstone, the world's first national park, has served time and again as a testing grounds for visitor desires.

Between 1896 and 1907, for example, there actually was a zoo of sorts in the park. One entrepreneur, E.C. Waters, managed to convince park managers to let him use Dot Island in Yellowstone Lake as a zoo with bison and elk. He would charge visitors to ferry them via his Yellowstone Lake Boat Company to the island so they could get a close-up view of the wildlife. (Today, of course, there are countless places in the park to get such views.) Each fall the animals would be taken off the island and penned next to the Lake Hotel for the winter. Hay cut in the Hayden Valley would be used for feed, according to Aubrey Haines' The Yellowstone Story.

And, of course, before the Craighead brothers did their voluminous and groundbreaking research into Yellowstone's grizzly bears, park visitors would head nightly to designated "feeding grounds" to watch black and grizzly bears feast on the day's garbage.

Prior to the end of World War II, parks attracted mostly the affluent, those who could afford to take summers off and traverse the West's iconic parks. After the war, the evolution of the car unleashed blue-collar Americans on the parks, a rising tide that led to the Mission 66 program that was a crash-course of sorts in developing national park facilities to handle these growing crowds.

"While the buildings are certainly historic, some visitors maintain that the defining architectural features of huge parking lots, cavernous public spaces and sloped rooflines have not aged well," Xanterra notes in a release. "Since the National Park Service is increasingly pursuing public transportation options, perhaps those vast parking lots will someday be filled by more buses than cars."

Ahh, yesteryear. Wasn't it grand? Or was it? Here's more from Xanterra's time capsule:

* Until recently, gentlemen were required to wear jackets to dinner at the Furnace Creek Inn Dining Room at Death Valley National Park. The dress code has been relaxed, but the restaurant still requests that guests do not wear shorts, tank tops, or T-shirts.

* Though today it is considered one of the most elegant of all national park lodges, visitors to the Lake Yellowstone Hotel prior to 1980 would have discovered an aging and neglected lodge that revealed little of famed architect Robert Reamer’s original vision. There was even talk of tearing down the hotel. Thanks to more than a decade of renovations the hotel was restored to its original grandeur. The National Park Service is planning yet another major renovation to the venerable hotel.

* The Crater Lake Lodge in Crater Lake National Park was also being considered for demolition. Right before the 1989 summer season, Park Service engineers determined the lodge’s Great Hall and other parts of the lodge required significant renovation. The Park Service launched a comprehensive renovation project that was completed in 1994. The magnificent lodge – with its inviting north-facing veranda – remains one of the jewels of national park system lodges.

* Those snowplanes that once skimmed around Yellowstone in winter? The planes had a two-person cab on three long metal skis. An airplane propeller on the back of the plane blew the vehicle down snow-covered roads, but the planes never left the ground. In 1949, 35 visitors entered the park in snowplanes from the gateway community of West Yellowstone. By 1955, snowcoaches began carrying winter visitors to the park, and in 1963, the first travelers entered the park on snowmobiles. Snowplanes were eventually discontinued, but snowmobiles – vastly improved from the original noisy and polluting machines – as well as snowcoaches still ferry visitors during the park’s winter season.

“If you look closely you can find reflections of each generation’s values and concerns in the Park Service policies,” says Mr. Hartvigsen. “We cannot imagine feeding wildlife, but it was a sanctioned activity until the ‘70s. And separating the genders in public spaces is downright laughable to most of us. It will be interesting to see what the next generation of park managers decides to change and what they find strange about the way parks have been managed during the first decade of the new millennium.”