Despite the elements, Mount Rushmore stays in mint condition for one reason: sustained aerial maintenance by the park rangers that patch up the massive sculpted rock.

The park rangers rappel from the top of the 86-year-old monument to patch cracks and install strain gauges near the Abraham Lincoln structure’s nose and hairline. “The first time is the hardest. After that, doesn’t bother me,” says park ranger rope access team member, Jim Manwell. Rangers like Manwell regularly accomplish tasks that rival typical extreme outdoor feats. Just as Jimmy Chin skied Grand Teton and Alex Honnold climbed Yosemite, the park rangers here have their own National Parks epic challenge to conquer.

The Rushmore rappel team works over 500 feet up from the visitors’ center. White lead and linseed oil stop the cracks in their tracks for a couple of years at least. The rangers keep at it year round to keep Rushmore on solid ground.

The efforts seen here will help maintain Rushmore’s structural integrity of for the next 10,000 years.