Now some of those unprotected places are threatened by the surge in U.S. energy development. One park entrance is already marred by a major oil well, and formerly wide-open vistas are littered with pump jacks and drill rigs.

It’s time to protect these special places—and honor the original vision for the park—once and for all. President Obama can create the Greater Canyonlands National Monument using the same Antiquities Act that Republican and Democratic presidents used to establish four out of five of Utah’s national parks.

With this monument, we can finish what was started 50 years ago.

Just two years after Canyonlands National Park was created, I spent months traveling around red rock country filming Butch Cassidy and the Sundance Kid. There is a reason the film won an Academy Award for Best Cinematography: Much of it benefited from the spectacular vermilion sandstone of southern Utah as a backdrop.

A rugged territory of canyons and river gorges, Greater Canyonlands is an expanse of wilderness like no other. This is one of the largest roadless areas left in the lower 48 states—somewhere you can wander for days without a glimpse of pavement or telephone poles, a place of outlaws and visionaries. Butch Cassidy himself is said to have hidden in its canyon mazes. Edward Abbey called it “the most weird, wonderful, magical place on earth—there is nothing else like it anywhere.”

Standing at Dead Horse Point high above the Colorado River and looking out over the panorama of high mesas, deep canyon walls, and orange and pink rock formations sculpted by wind and water, it’s easy to see that the park boundaries failed to capture all the region’s natural treasures. Straight lines arbitrarily cutting across meandering rivers and ridgelines encompass only a portion of the living heart of red rock country.

That leaves the land around the park increasingly under siege from rampant oil and gas development, potash mining, and potential strip mines for tar sands oil—the dirtiest fuel on earth. Drilling activity has increased so much outside the Island in the Sky district of Canyonlands National Park that Moab residents have dubbed it “Oil Land in the Sky.”

The idea of drill pads, gas flares, and pipelines crisscrossing this glorious landscape is obscene. Wild places are an essential part of our American spirit. They belong to all of us, and we must protect them from reckless and polluting industries.

The time is now. As Canyonlands National Park celebrates its 50th anniversary and the Centennial of the National Park Service approaches in 2016, President Obama can fulfill the original vision for the park by preserving the entirety of this landscape for good.

This will not only safeguard a place of stunning beauty but also build on a distinctly American tradition—one carried on by both political parties and both state and national leaders—of conserving the wild places that sustain our nation’s rugged and independent character. Greater Canyonlands is one of them. Let’s protect it now.