Hi Kaitlyn, thanks for the question.  Mt. Rushmore is a carved stone statue in the hills of South Dakota and truly an amazing part of our American History.  You can learn a lot about the reason it came to be, how it was carved and much more on OhRanger.com.  Below is a sample taken from the website that is a good general overview. 

We're always here at OhRanger.com to answer your questions.  Make sure to tell all your friends!

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Mount Rushmore National Memorial

"The four figures carved in stone on Mount Rushmore represent the first 150 years of American history. The birth of our nation was guided by the vision and courage of George Washington. Thomas Jefferson always had dreams of something bigger, first in the words of the Declaration of Independence and later in the expansion of our nation through the Louisiana Purchase. Preservation of the union was paramount to Abraham Lincoln but a nation where all men were free and equal was destined to be. At the turn of the Twentieth Century Theodore Roosevelt saw that in our nation was the possibility for greatness. Our nation was changing from a rural republic to a world power. The ideals of these presidents laid a foundation for our nation as solid as the rock from which their figures are carved. Each man possessed great skills and leadership of the brand our nation needed for the times. Today millions of visitors come to see Mount Rushmore and gain inspiration from these four great men."

See here for how it was built:

http://www.ohranger.com/mount-rushmore/making-mount-rushmore