"You cannot improve upon it." So said President Theodore Roosevelt when he created Grand Canyon National Monument in 1908.

Photograph by Walter Meayers Edwards, National Geographic
  • On January 11, 1908, U.S. President Theodore Roosevelt made the massive Grand Canyon in northwestern Arizona a national monument, declaring “You cannot improve upon it.” Roosevelt, an avid hunter and naturalist, loved the American west. He made environmental conservation a priority during his presidency.

    The Grand Canyon is a gorge created by tectonic uplift of the Colorado Plateau. The Colorado River cut through the canyon’s striking red rock as the area was uplifted by geologic forces deep underground. Over the past 17 million years, the flow of the river’s water has carved the canyon to a depth of more than 1,829 meters (6,000 feet), and is still eroding the rock today. Roosevelt’s declaration of the area as a national monument ensured that more than 323,748 hectares (800,000 acres) of canyonland would remain untouched by human development. This means that future generations might enjoy it as he did.

  • Term Part of Speech Definition Encyclopedic Entry
    avid Adjective


    canyon Noun

    deep, narrow valley with steep sides.

    Encyclopedic Entry: canyon
    carve Verb

    to cut or slice through.

    conservation Noun

    management of a natural resource to prevent exploitation, destruction, or neglect.

    Encyclopedic Entry: conservation
    development Noun

    construction or preparation of land for housing, industry, or agriculture.

    ensure Verb

    to guarantee.

    erosion Noun

    act in which earth is worn away, often by water, wind, or ice.

    Encyclopedic Entry: erosion
    geologic Adjective

    having to do with the physical formations of the Earth.

    gorge Noun

    deep, narrow valley with steep sides, usually smaller than a canyon.

    Encyclopedic Entry: gorge
    Grand Canyon Noun

    large gorge made by the Colorado River in the U.S. state of Arizona.

    national monument Noun

    federal land set aside to protect objects of scientific and historical interest.

    naturalist Noun

    person who studies the natural history or natural development of organisms and the environment.

    plateau Noun

    large region that is higher than the surrounding area and relatively flat.

    Encyclopedic Entry: plateau
    priority Noun

    something having more importance than others.

    tectonic uplift Noun

    movement of plates beneath the Earth's surface that causes one part of the landscape to rise higher than the surrounding area.

    Theodore "Teddy" Roosevelt Noun

    (18581919) 26th president of the United States.