On learning that weather erodes granite one inch every 100,000 years, sculptor Gutzon Borglum added an extra three inches to each president’s features on Mount Rushmore.

“Three inches would require 300,000 years to bring the work down to the point that I would like to finish it,” he said. “In other words, the work will not be done for another 300,000 years, as it should be.”

(Thanks, Matt.)