Photos of Yellowstone National Park taken in 1871 and today look incredibly similar

In the summer of 1871, photographer William Henry Jackson set out on an expedition to document the untamed, other-worldly beauty of a region that would become the country's first national park. At the time, Congress was reviewing legislation to establish Yellowstone National Park, but it needed convincing.

They heard accounts of the wonders explorers had seen - "spouting geysers, towering waterfalls and a huge, pristine mountain lake," as photojournalist Bradly J. Boner told Tech Insider. But they "seemed too extraordinary and were often dismissed as campfire tales."

Jackson returned to Capitol Hill with an exhibition of photos that diminished all doubts. Yellowstone National Park was born, much to his credit.

Boner recently returned to the Great American West to recapture Jackon's iconic images. To celebrate the National Park Service's 100th anniversary, we've published a selection here.