In the summer of 1869, a one-armed Civil War veteran set out on a journey that many believed would end in disaster. Armed with little more than small wooden boats, scientific instruments and determination, John Wesley Powell led nine men into the largely unmapped Colorado River, hoping to answer one of geology's biggest questions: How was the Grand Canyon formed?
The expedition, which began on May 24, 1869, from the Green River in present-day Wyoming, was unlike any previous journey into the canyon. Powell and his crew battled violent rapids, towering canyon walls, dangerous currents and dwindling food supplies as they navigated one of North America's most unforgiving landscapes. Every mile forward came with the risk of losing boats, equipment—or even lives.
