Obviously, this is a must-see in Peru and one of the more beautiful places you will visit. Just wanted a add a few notes about our experience. Tickets: For anyone who is not part of a tour and looking to get tickets in advance, this is an immensely frustrating process. The government website proves non-functional for most people, and the hotels will simply direct you to the tour options they or their travel agency partners offer rather than assist you with tickets. We thus planned to buy them in Cuzco before we headed out to Aguas Calienties, only to be told the ticket office in Cuzco was closed not the weekends. So we had to buy the tickets at the office in Aguas Calientes upon arrival, and fortunately they were not sold out (we traveled in late March/early April) even when we arrived late afternoon. Tickets are twice as expensive for foreigners as they are for Peruvians, and do not include tickets for the bus to the site, which are purchased separately. Tickets are also only good for one calendar day of entry, so if, like us, you want to enjoy the site on two days back to back, you are forced to suck it up and pay for park entry and the bus twice. *Sigh.* The bus: Only way to get up if you don't want to hike up, this ride is not for the faint of heart, though you experience some beautiful, unique views. Road is extremely narrow and bumpy with no guard rails, so if this sort of thing makes you nervous just be warned. Restrooms: Obviously there are no restrooms in the park, but there is one at the entrance. The charge you 1 sole to use it, and is has no paper towels or toilet paper, as was the case with bathrooms at the ticket office in Aguas Calientes. Time to go: On our first day we went arrived late, coming up on one of the last buses, and the site was fairly quiet, with the sun shining but not blazing hot. On our second day we arrived closer to noon and as expected, the site was pretty packed with tour groups. Sun came out hotter than later in the day. Can't speak to the morning, but we heard it tends to be cloudy with reduced visibility early. Water: We heard you couldn't bring plastic bottles, but we had them in our bag and no one said anything at bag check. Finally, given the tourist masses that come I didn't expect the walks around the site to be very strenuous, so I was surprised to find the pathways to be somewhat challenging and uneven. Just something to know even if you are fit. Guides: There are guides at the entrance who will offer their services, but we opted to skip this on both visits. Given how little is really known about the site and how much is speculation I didn't think it would add much to the experience, and overhearing some of the other guides we felt ok about opting out, but it's an option if you want more context. We spent about 2 hours each day at the site and could have spent more, but were satisfied with how much we saw.