Despite being one of the most famous and most-visited attractions in the United States, Grand Canyon National Park still holds some surprises. Here are a few facts about the Grand Canyon you probably don’t know.

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7. We don’t really know how old it is.

It has long been believed that the Colorado River began carving the Grand Canyon about 6 million years ago, but a 2012 study contained a real shocker, suggesting that the process may have begun as far back as 70 million years. In all likelihood, the Grand Canyon as we know it today started out as a series of smaller canyons 70 million years ago, but the majority of the canyon did not begin to take shape until much more recently.

The Grand Canyon
The Grand Canyon
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