[ucarion]

This is what I thought at first too, but as others have pointed out, there are lots of nearby mountains that block the horizon in the Himalayas.

Here's a panorama using the same tool the article uses:

http://www.udeuschle.selfhost.pro/panoramas/panqueryfull.asp...

The furthest point from the top of Mt. Everest that you can see is 303km away, and it's tucked between two faraway mountains.

Edit: I'm sorry, but this comment is wrong. I used the tool incorrectly. In fact, longest LOS from Everest is 8th on the list, and is 455km long. I assumed that when the tool auto-completed Everest it would give me the peak, but it did not.

[ucarion]

In case anyone else was wondering, the longest line of sight from Mt. Davidson, the tallest hill in San Francisco, is 148.9km, looking southeast over the length of the bay. Here's a panorama:

http://www.udeuschle.selfhost.pro/panoramas/panqueryfull.asp...