Norris Geyser Basin was a bowl-like area containing 30 geysers, most of which erupted every few seconds or minutes, so that there were always several in action.

Written By: Eliza Berman

There is an origin story about Yellowstone National Park that involves weary explorers sitting around a campfire, extolling the beauty of the land they’ve just seen and vowing to ensure it becomes a public park for all to enjoy. It’s a vision of altruism and environmentalism that suits the founding of the world’s first national park only it’s not entirely true.

The members of the 1870 Washburn-Doane Expedition did likely gather for campfires as they explored the region’s geysers and rivers and waterfalls, and they did likely discuss the best use of the land they were exploring. But, as with so much of American history, there were significant corporate interests at play. Yellowstone might never have become the public parkland it is today if not for the Northern Pacific Railroad Company.

Before the explorers set out on their expedition, Northern Pacific was strategizing to expand across the Montana Territory. An influx of tourism in the region would be a boon to business, so a railroad financier, Jay Cooke, began lobbying for an expedition. To drum up excitement back East, one member of the expedition, a politician named Nathanial P. Langford, toured the country giving lectures about the beauty of Yellowstone. Meanwhile, Northern Pacific subsidized an artist to sketch images of the park for display in Washington, D.C.

In March of 1872, less than two years after the expedition, Congress enacted the Yellowstone Park Act, ensuring that the land would remain under the purview of the Department of the Interior rather than being divvied up among private individuals—an arrangement that would attract visitors to the area, which would be sure to benefit big business like the railroad company.

More than 70 years into the park’s existence, LIFE dispatched Alfred Eisenstaedt to photograph its geographic features, during a summer that was shaping up to be Yellowstone’s biggest yet for tourism. In that record year, 1946, the park had more than 800,000 visitors. In 2018, it had 4.1 million visitors. Though the idea might seem incongruous, all of the many millions of people who over the decades have encountered Yellowstone’s bison and watched Old Faithful blow have corporate interests to thank for one of America’s greatest natural wonders.

Liz Ronk edited this gallery for LIFE.com. Follow her on Twitter @lizabethronk.

Old Faithful, Yellowstone National Park, 1946. Alfred Eisenstaedt The LIFE Picture Collection/Getty Images

Castle Geyser, Yellowstone National Park, 1946. Alfred Eisenstaedt The LIFE Picture Collection/Getty Images

Norris Geyser Basin was a bowl-like area containing 30 geysers, most of which erupted every few seconds or minutes, so that there were always several in action. Alfred Eisenstaedt The LIFE Picture Collection/Getty Images

Riverside Geyser was just as regular as Old Faithful, erupting every seven hours. Alfred Eisenstaedt The LIFE Picture Collection/Getty Images

Spectators waited for Giant Geyser, which erupted every six to 16 days. Alfred Eisenstaedt The LIFE Picture Collection/Getty Images

A graffiti-covered sign at Yellowstone National Park, 1946. Alfred Eisenstaedt The LIFE Picture Collection/Getty Images

Giant Geyser, Yellowstone National Park, 1946. Alfred Eisenstaedt The LIFE Picture Collection/Getty Images

Morning glory pool, shining beautifully, was an extinct geyser. Alfred Eisenstaedt The LIFE Picture Collection/Getty Images

Grotto Geyser showed the cone-like formation of whitish silica deposited around its opening during centuries of activity. Alfred Eisenstaedt The LIFE Picture Collection/Getty Images

Jupiter Terrace was a series of grayish-white pools and falls formed by the action of large hot springs at its top. Alfred Eisenstaedt The LIFE Picture Collection/Getty Images

The Grand Canyon of Yellowstone was gouged deep into the soft volcanic rock by the rushing waters of the Yellowstone River, leaving fantastic shapes such as the 260-foot “needle” shown at lower left. The picket-fence effect along the top of the cliff is a layer of ancient lava hardened by cooling and shrinking into columns of basalt 25 feet high. Alfred Eisenstaedt The LIFE Picture Collection/Getty Images

The Lower Falls of Yellowstone River had a perpendicular drop of 308 feet, which was about twice the height of that of Niagara Falls. Alfred Eisenstaedt The LIFE Picture Collection/Getty Images

Some tourists cooked over hot springs, despite the park officials frowning on this. Alfred Eisenstaedt The LIFE Picture Collection/Getty Images

Visitors bought about three million postcards and scenic photo folders a year. Alfred Eisenstaedt The LIFE Picture Collection/Getty Images

The hut at Mammoth Hot Springs was made of old elk antlers, which were also sold to visitors as souvenirs. Alfred Eisenstaedt The LIFE Picture Collection/Getty Images

A mother moose and her baby at Yellowstone National Park, 1946. Alfred Eisenstaedt The LIFE Picture Collection/Getty Images

Yellowstone National Park 1946 Alfred Eisenstaedt The LIFE Picture Collection/Getty Images

Bears, both black and grizzly, were common, particularly around garbage dumps. Alfred Eisenstaedt The LIFE Picture Collection/Getty Images

Pillow covers of brightly-colored rayon satin, adorned with maps and the scenic wonders of Yellowstone, sold rapidly at $1.25. Alfred Eisenstaedt The LIFE Picture Collection/Getty Images

Free pop, in the form of natural carbonated water with lemonade flavor, gushed in continuous streams from the rocks which lined the highway near Apollinaris Springs. Alfred Eisenstaedt The LIFE Picture Collection/Getty Images

Cars lined up to enter Yellowstone National Park, 1946. Alfred Eisenstaedt The LIFE Picture Collection/Getty Images

Trailer camps charged tourists $1 a day, and many visitors settled down in them, living on fish they caught. After a month visitors had to move on to another camp in the park. Alfred Eisenstaedt The LIFE Picture Collection/Getty Images

Trailer park, Yellowstone National Park, 1946. Alfred Eisenstaedt The LIFE Picture Collection/Getty Images

This Las Vegas blackjack dealer and his wife spent the summer in a tent at Yellowstone. Alfred Eisenstaedt The LIFE Picture Collection/Getty Images