The longest line of sight / all the views in the world

All the Views in the World is an attempt to calculate how far a human can see from any point on Earth to determine where you can see the farthest—the longest line of sight. Apparently, if someone stands in just the right spot "between an unnamed Himalayan ridge near the Indian-Chinese border and Pik Dankova in Kyrgyzstan" and it is a perfectly clear day, they can see just over 530km/329 miles.

Found thanks to Rusty of Today in Tabs.