A glacier that is now the Colorado River passed through over thousands if not millions of years.

started out as a tiny stream and eroded away the earth until it eventually formed a huge canyon and now the stream is at the bottom.

Glacial movements. Large masses of ice receeded from the south to the north as the ice age ended and cut large crevasses into the earth.

That's a great question, because scientists still don't really know. They used to think that it formed during the world's last period of mountain formation. They thought that the river had established it's course, and maintained it by eroding it's bed at the same rate as the land rose during subsequent earth movements. But these movements ended more than 50 million years ago, and no older river deposits have been found downstream from the canyon. All that debris had to go somewhere, and it has not been found. In fact there is evidence that while the river above the canyon established it's route 30 to 40 million years ago, the river's course below the canyon was formed less than 9 million years ago. Before then, the river must have followed another route to the sea, one that has yet to be found.

Wikipedia: Creation of the Grand Canyon Uplift of the Colorado Plateaus forced rivers to cut down faster.The Laramide orogeny affected all of western North America by helping to build the Cordilleran Mountain Range (of which the Rocky Mountains are a major part). This major mountain-building event started near the end of the Mesozoic (around 75 million years ago) and lasted well into the early Cenozoic. A second period of uplift started 17 million years ago, creating the Colorado Plateaus (the Kaibab, Kanab, and Shivwits plateaus bound the northern part of the canyon and the Cococino bounds the southern part). However, for reasons poorly understood, the beds of the Colorado Plateaus remained mostly horizontal through both events even as they were uplifted an estimated 9000 feet (2700 m). One hypothesis suggests that the entire plateau shifted in a clockwise rotation during the uplift and this helped to maintain its stability. Before the uplift the plateau region was about 1000 feet (300 m) above sea level and bounded by high mountains to the south and west. In middle Tertiary time (about 20 million years ago) tensional forces (crustal stretching) created and expanded faults in the area and caused some moderate volcanic activity. To the west, these forces created the Basin and Range province by forming long north-south-trending faults along which basins (grabens) dropped down and mountain ranges (horsts) were uplifted. The extreme western part of the park is intersected by one of these faults, the Grand Wash. The Colorado River had cut down to nearly the current depth of the Grand Canyon by 1.2 million years ago.Continued uplift of the Colorado Plateaus created monoclines and also increased the elevation of its plateaus. This steepened the gradient of streams flowing in the Colorado Plateaus province. The ancestral Colorado River was a landlocked river until 5.3 million years ago (see below). Before that it had a series of temporary base levels (lowest points) in large lakes in the Colorado Plateaus in the early Tertiary and possibly the Basin and Range by the middle Tertiary.[13] The opening of an arm of the Gulf of California 5.3 million years ago changed the direction of nearby streams toward the sagging and rifting region. The upstream uplift and downstream sagging caused streams flowing into the gulf to run and downcut much faster. Soon (geologically speaking) headwater capture consolidated these streams into one major river and associated tributary channels—the modern Colorado drainage system. The most important consolidation occurred when a separate preexisting river that was carving a channel into the San Andreas Fault and out into the gulf likely captured the landlocked Colorado.[14] Excavation of the eastern part of the Grand Canyon began previous to this but was greatly accelerated and expanded west afterward. Ice ages during the Pleistocene brought a cooler and wetter pluvial climate to the region starting 2 to 3 million years ago. The added precipitation increased runoff and the erosive ability of streams (especially from spring melt water and flash floods in summer). With a greatly increased flow volume, steepened gradient, and lower base level, the Colorado cut faster than ever before and started to quickly excavate the Grand Canyon two million years before present, almost reaching the modern depth by 1.2 million years ago.[15] Vulcan's Throne volcano above Lava Falls. Lava flows like this heavily eroded remnant once dammed the Colorado River.In later Pleistocene time, around one to two million years ago, basaltic lava covered part of the area and in places cascaded down side canyons, even damming the western part of the canyon between miles 178 and 188 (286 and 302 km) in the Mount Trumbull area. The river was dammed in this way at least 13 times from 1.8 million to 400,000 years ago.[16] Three of these lava dams were over 1000 feet (300 m) high, forming lakes similar to reservoirs such as Lake Mead or Lake Powell. Some of the lakes were over 100 miles (160 km) long and 200 to 2000 feet (60 to 600 m) deep for many years, before finally over-topping the dam and eroding much of it away in massive cascading waterfalls (it took about 20,000 years from start of each dam's formation to its destruction). Cinder cones and the remnants of lava flows are visible in the Toroweap area, and the remains of some of the dams exist today as rapids such as Lava Falls.

If you're an evolutionist, this should explain it. http://www.teachersdomain.org/resources/ess05/sci/ess/earthsys/canyon/ If you're a creationist, this should be for you. http://www.rae.org/bits15.htm

Paul Bunyan hitched a plow to Babe the Big Blue Ox...

According to what my wonderful science teacher taught me. The Grand Canyon was formed by huge glaciers cutting deep into the mountains forming what we called crevasses. Then the rivers and small tributaries carved shape into the Canyon eroding loads of the sediments. This process repeated constantly at a fast pace, made the Grand Canyon.

It is made by the Colorado river over lots of years

Hmmm!i like to believe the jew version but it would have cost too much! maybe an earthquake millions of years ago split the earth what about the egyptian connection? apparently the caves in the canyon have been sealed top secret???