This 12m long sliver of granite is located at Half Dome Yosemite, California.
Named the "Thank God Ledge", it is the only way to get beyond the Visor, a massive roof that looms over the Regular Northwest Face route of the Yosemite National Park.
Most people crawl to get across, but some choose to walk it face out, since that's "cooler."
The 30 seconds it takes to get across requires absolutely no technical climbing skill.
But even the most experienced climbers say it's sobering to look at 548m of air, reports Before It's News.
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