2 ms·

Also spell out what "line of sight" means in this context.

• shric 8mo ago
  It means a straight line that you can see to the other end while still being on the ground. Long lines of sight are between stuff at high altitudes because at near sea level the horizon becomes a problem after only a few miles/kilometres.
  • stevage 8mo ago
    Yes, I worked it out - just a suggestion for making the article better.