Pete McBride got up one morning planning to paddle a small raft down the Colorado River to the sea. He was shocked to find he had to stop partway—when the river ran out of water.

McBride began his career as a photojournalist documenting expeditions in some of the most challenging locations in the world—from Mount Everest to Antarctica to the Ganges River. His photos had been appearing in leading magazines for 10 years when he discovered the plight of the Colorado River, which flows from the Rocky Mountains in Colorado, United States, southwest to northern Mexico. That experience convinced him he needed to do more than simply record what he saw. He has combined photography with advocacy to protect fragile resources of his home region, the American Southwest, adding writing and filmmaking to his expertise.

McBride began his work for the Colorado River by tracing the river mostly from the air while his collaborator, Jon Waterman, traveled at stream level. His aerial photographs and Waterman’s story led to a short film, Chasing Water, and a book, The Colorado River: Flowing Through Conflict. Both highlighted the human use of water from the Colorado River, which has turned the once-jungle-covered delta into a dried-up, barren flatland.

McBride’s interest in the Colorado River led him to another natural treasure under threat: the unique scenery and ecosystem of the Grand Canyon, sculpted by the Colorado River. With writer Kevin Fedarko, the two linked eight trips to complete a 1,207-kilometer (750-mile) sectional thru-hike the entire length of the canyon, a feat few have attempted or accomplished. “More people have orbited the [sic] Earth than have done a connected end-to-end walk of the Grand Canyon,” McBride claims. Along their trail-less journey, they faced extreme temperature swings (from snow to 44.44 degrees Celsius [112 degrees Fahrenheit]), extreme lack of water, and dangerously exposed climbing conditions. But more importantly, they learned from many canyon lovers, park officials, and Native tribal residents throughout the area that development plans are poised to forever change one of America’s most iconic landscapes. National Geographic Adventure listed McBride and Fedarko among the “Adventurers of the Year” in 2017, and the project resulted in an award-winning National Geographic documentary Into the Grand Canyon and an award-winning book Between River and Rim.

McBride continues to travel and speak about the river and the canyon. In so doing, he advocates for the preservation of freshwater, rivers, and wild places everywhere on Earth, a cause inspired by his “front yard,” the Colorado River. “It seems the river has called me,” he says, “and it keeps calling me back.”