The Danish-American sculptor Gutzon Borglum began carving the heads of four presidents out of South Dakota's Mount Rushmore in 1927, embarking on an ambitious project to build one of America's most iconic memorials. Today, the heads of George Washington, Thomas Jefferson, Abraham Lincoln and Theodore Roosevelt attract more than 2 million visitors every year.
But construction was predictably laborious, and Borglum died in 1941 before he could see his project finished. His son, Lincoln Borglum, completed the sculpture later that year. Today, on the 84th anniversary of the Fourth of July dedication of Washington's head in the early years of carving, TIME looks back at the construction of the memorial that immortalized four presidents.