According to the standard formula for the curvature of the earth, this distance would mean a fall of over 15 km
LINE OF SIGHT
Longest photographed line of sight: 443 km
The longest line of sight on Earth photographed is 443 km (275 miles), by Mark Bret Gum (Spain), from Pic de Finestrelles, Spain, to Pic Gaspard, France, on July 13, 2016.
The photograph was taken with a Panasonic Lumix FZ72, after long preparations to choose the optimal date and location. The photo was taken as the sun rose behind Tête Chabrières and Puy de la Sèche, to highlight these peaks on the horizon.
The photo was taken from the Pic de Finestrelles, in the Pyrenees Mountains. Pic Gaspard, Alps, can be seen in the center of the photo, 443 km away.