Numbers, however, do not reflect qu' part of l' history of the canyon and simply allusion to the magic of its thousand nuances, of the layers, arrows, and throats. L' place is more than the sum of its parts, d' as much more than nor l' eye nor l' spirit of the spectator can include d' more; a small portion of this one at the same time. Like John Wesley Powell, of which the party, in 1869, became the first to cross the canyon of the river, writing: “You cannot see the Large Canyon in only one point of view, like s' it s' d' acted; an immutable spectacle from which a curtain could be levées." At the bottom of the canyon, one mile-below of the edge, the river Colorado sections of granite through the throat, which exposes some of oldest visible rocks the n' import where on the ground. Nearly two billion d' years, the Vishnu schist is the black residue shining d' a range, once imposing mountains. Some 500 d' million; years after its formation, of vast rifting and faults posed it the rocked position, coloured sediments of the series Large Canyon at the schist top. Ten layers distinct from sandstone, limestone, schist and testify to l' advances and the withdrawal of the old seas, the construction and wear of the mountains, the meanders of the rivers of more than 600 d' million; years.

With each rim, visitors to perch itself at the top of the creamy date Kaibab cliffs of limestone strewn d' fossil sponges, corals, snails and the molluscs which lived a hot inland sea it ya 240 d' million; years. Although layers of rocks, once covered this old sea-bed, all the geological signs of l' Mesozoic era, more recent and cenozoic did without it ya the glosses. In comparison with nearly two billion process year of deposits, l' erosion imposed a sustained rhythm. The Large Canyon is itself lower than six d' million; years, created only since the Colorado river changed course and started to run through the plate of Colorado ancestral. In hardly two d' million; years, the river sliced with less than 500 feet above its current depth. Wind, rain, snow, heat, cold and helped the process. So has l' flow of hundreds d' affluents, of which much is dry washings, filled in an intermittent way by the cast iron of snows and the storms d' summer. During let us éons these flows created " a composite of thousands, tens of thousands, throats”, like Powell l' astonishment. “Each one of these… is a world of beauty in oneself”.

The Large Canyon is not only one section of l' geological history d' North America, but also a transverse section d' écozones. Between the rim and river, the travellers to find the same variety of ecological areas qu' they would meet at the time d' a voyage coming from Canada towards Mexico - covered with snow forest with persistent sheets of the boreal zone in the arid depths of lower Sonora, where the estival temperatures to plane above 100oF and tough shrubs as creosotes it and ocotillo prevail. In all, the Large Canyon constitutes a habitat rich and diversified of more than 400 species the vertebrate ones and 1500 plants.
The presence of l' man here goes back to at least 4000 years, while starting with the hunters-gatherers who deposited Split delicate animal figures willows in the caves limestones. Before disappearing towards 1150 AD, former Pueblo people which had lived in and around the canyon for one millenium or more left a rich person heritage of the pottery, baskets, pictograms and attics and other structures on thousands of sites. The Havasupai people in the area aujourd' today trace of their presence to hundreds d' years. During the 20th century, the human ones had an impact much major on the Large Canyon than in l' together past.
In 1900, the canyon was already a well-known destination, thanks to the reports written by the explorers and of the scientists and the luminous fabrics of Thomas Moran. And after Large National Canyon Park was created in 1919, the number of visitors continued d' to increase exponentially: Approximately five million people visits from now on each year the canyon in the car, with foot, the top of the mules, on motorized rafts, and helicopters. Some of the human consequences, like the sight-haze sullying the drift in powerplants and urban centres, was indirect. In 1963, Glen Canyon Prejudice finished the free flow of the Colorado river to l' entered of the Large Canyon, and that only action changed the canyon more than any other event with l' time of l' man. For John Wesley Powell one century earlier, the noise of cascade in the canyon was “a symphony of innumerable melodies.
But with the simple pressure on a switch, flow and the backward flow which worked the complex ecosystems of the canyon to the course d' innumerable millenia, were stopped. Since 1963, the ecological richness of the canyon strongly decreased. In 1996, the civils servant opened Glen Canyon Prejudice for a flood d' one week of test conceived to imitate the natural floods. Even if it n' the right of ecological imbalances does not have which s' was seized, l' event marked an important recognition of the role that the requirements of nature, though easily adulterated, have their own logic.