The Gand Canyon is one of the largest miracle of nature in the world. The canyon is:

at width of 6,5-29 kilometre (average 19km)
at lenght of 446 kilometre
at deep of average 1600 metre
At this passage the Colorado River has a lenght of 350km and a width of 90m, a gradient of 670m and 160 rapids.
The Grand Canyon is visited by 4 Millions of people every year.
As well more than 250.000 people take part in a flight over the Canyon.
Approximate 2000 persons will conquer the Colorado River by dinghys.