Put on your party hats! 2016 is not just the year to elect a new president. It’s also a time to celebrate a memorial to four past presidents. This year marks the 75th anniversary of the completion of Mount Rushmore National Memorial. The famous South Dakota monument features the faces of presidents George Washington, Thomas Jefferson, Theodore Roosevelt, and Abraham Lincoln. Each face is 18 meters (59 feet) tall. 

Sculptor Gutzon Borglum began constructing the memorial in 1927. His son, Lincoln, finished it in 1941. Mount Rushmore was a good place to build the monument because the mountain is made of granite. This type of rock contains superstrong substances like quartz—a mineral that takes a long time to break down. Granite carvings like Mount Rushmore can last for thousands of years!