I negotiated a big discount to stay at the Sanctuary Lodge. This meant I could visit the ruins at night (by buying another $20 ticket for 6pm to 9pm). Unfortunately, it was cloudy so I didn't go in.
However, the other advantage is being able to get into the ruins before anyone else. They open at 6am with the first bus arriving just before 7am. I looked out my window at 5am hoping for clear sky so I could watch the sunrise from the ruins. It was still cloudy so I went back to bed.
At 6am I went in again but it was not anything like as good as the previous night's cloudless sunset. The weather changes very quickly. The previous day it started cloudy, became sunny, cloudy again, sunny, light drizzle, pissing rain and a cloudless sunset. This is, apparently normal.
I returned to the hotel for a ludicrously expensive breakfast.
I wanted to climb Huayna Picchu (the classic big bump) even though it looked rather steep. However, my resolve had been affected by a French girl disappearing at about 6.30pm the previous night. Her three friends were anxiously shouting out her name and a guard was calling for assistance on his radio.
She was still missing th next morning.
I spoke to one of the managers at the hotel. Apparently about five to ten tourists are severely injured or die every year. Most of the accidents happen when climbing Huayna Picchu.
I signed the entrance book and set off. I had only been walking for ten minutes when I changed my mind and gave up. I signed myself back in and in the comments section entered 'too scared'.