A powerful and inspiring landscape, the Grand Canyon overwhelms our senses through its immense size; 277 river miles long, up to 18 miles wide, and a mile deep. Grand Canyon National Park became a national park in 1919, signed by President Woodrow Wilson. President Theodore Roosevelt visited the rim in 1903 and exclaimed: "The Grand Canyon fills me with awe. It is beyond comparison--beyond description; absolutely unparalleled throughout the wide world .... Let this great wonder of nature remain as it now is.
The creation of the park was an early success of the environmental conservation movement; its National Park status may have helped thwart proposals to dam the Colorado River within its boundaries. The Grand Canyon itself, including its extensive system of tributary canyons, is valued for the exposed layering of colorful rocks dating back to Precambrian times. It was created through the incision of the Colorado River and its tributaries after the Colorado Plateau was uplifted and the Colorado River system developed along its present path.