About half way up a section of the track called, rather accurately, the Devil's Staircase. It's not quite steep enough to be a climb, but too steep to be a walk. Add the treacherous loose scoria and a case of delayed onset muscle soreness from Thursday's gym session and you have something really quite unpleasant. Going to the gym was probably a mistake.
If you look carefully, you might be able to see the line of people coming up. Or you could cheat and look here.