The greatest sadness is to see the amount of wonders destroyed by the Spanish invaders.
Reflecting on it when I got home, I couldn't understand what made me not decide to go earlier in my life. I had Machu Picchu at the top of my bucket list since childhood as I'm sure many do, but it was never at the top for some reason. That was such a big mistake and I wish I went to Peru a long time ago, there's no other place like it, and it only gets harder to travel there the older you get since the altitude is rough. The number of elderly and retired people I saw struggling in Cusco from altitude sickness was too high. I heard a horror story of someone needing to spend a week in the hospital and unable to see a single site.