This colossal sculpture showcases the iconic faces of four former U.S. presidents intricately carved into a mountain in South Dakota's Black Hills. The 60-foot-tall profiles of George Washington, Thomas Jefferson, Theodore Roosevelt and Abraham Lincoln were intended to represent the first 150 years of America's history and cultural heritage. Historian Doane Robinson came up with the idea to promote tourism and artist Gutzon Borglum designed the sculpture itself, modifying the design repeatedly to accommodate the unforgiving rock. Though the artist passed away before the monument's completion, more than 400 workers helped bring his vision to life.