Peru gets sold as a single postcard, that early-morning shot of Machu Picchu with the light coming up over Huayna Picchu, and for a lot of travelers that is the entire plan: fly to Cusco, get to the ruins, get the photo, go home. The trip works far better if the ruins are treated as the payoff of a longer, slower build rather than the whole point, because the altitude, the logistics of permits, and the Sacred Valley in between are where most of the actual experience happens. None of it is complicated once you know the shape of it, but almost all of it goes wrong for people who show up assuming it works like any other city break.
Cusco: acclimatizing to the Andes
Cusco sits at roughly 3,400 meters, high enough that a meaningful share of visitors feel some version of altitude sickness in the first 24 to 48 hours: headaches, breathlessness on stairs, disrupted sleep, occasional nausea. The single best fix is unglamorous and free, which is arriving with at least two full days in Cusco before attempting any real exertion, including the Sacred Valley's outdoor sites. Coca tea is offered everywhere and does take the edge off mild symptoms, but it is not a substitute for the extra day, and pushing through a bad headache on schedule rather than resting through it is how minor altitude discomfort turns into a ruined day.
The city itself rewards the slow pace altitude forces on you. The Plaza de Armas, San Blas's steep cobbled streets, and San Pedro Market are all walkable at an unhurried pace, and Cusco's Spanish colonial architecture built directly on top of Inca stonework, visible in walls like the twelve-angled stone on Hatun Rumiyoc, is a preview of the fusion you see at a larger scale later in the trip. Some travelers skip Cusco almost entirely to save time for Machu Picchu; that trade is a mistake, since Cusco is a legitimate multi-day destination on its own and the acclimatization time is not optional anyway.
The Sacred Valley: Ollantaytambo and Pisac
The Sacred Valley, the Urubamba river valley running northwest from Cusco, is lower in elevation than the city itself, which makes it a genuinely useful acclimatization stop rather than just a scenic detour. Pisac combines a lively artisan market with a hillside archaeological site of agricultural terracing that is far less crowded than Machu Picchu while illustrating the same Inca engineering. Ollantaytambo is the valley's standout: a working town built on genuine Inca foundations, with residents still living in centuries-old walled compounds, plus a fortress-temple complex on the hillside above that most visitors underrate relative to how much time they allocate to it.
Ollantaytambo also matters practically, because it is the departure point for the train to Aguas Calientes, the town below Machu Picchu. Basing yourself in the valley for two or three nights rather than day-tripping from Cusco cuts down on transit time, keeps you at a friendlier altitude for sleeping, and means you arrive at the train station without a two-hour drive first. Moray's circular agricultural terraces and the Maras salt pans, both a short taxi ride from Ollantaytambo's area, round out a two-day valley itinerary if you have the time to spare.
Machu Picchu: permits, routes and timing
Entry to Machu Picchu itself is capped and ticketed by circuit, and tickets for popular circuits and the Huayna Picchu or Machu Picchu Mountain add-on hikes sell out weeks to months ahead in the June-to-August high season. Booking through Peru's official Ministry of Culture site directly is cheaper than going through a reseller, but the interface is clunky and circuit availability is not always intuitive, so building in buffer time to sort tickets before finalizing train and hotel dates saves real stress. The standard visit is a fixed circuit walked in one direction; the mountain hikes require a separate, additional ticket and a specific entry time slot, and are worth the extra planning for the elevated overview they give of the whole site.
Getting to the site from Aguas Calientes is either a 25-minute bus ride or roughly a 90-minute uphill walk starting well before dawn if you want to catch sunrise; the buses start running around 5:30am and the line for them can be substantial in high season, so budget real time rather than assuming you will walk straight on. Weather at Machu Picchu is genuinely unpredictable regardless of season, with cloud cover or rain capable of arriving any month, so a flexible attitude about the "perfect light" photo matters more than picking a specific month to chase it.
The Inca Trail versus alternative treks
The classic four-day Inca Trail is the only trek that ends by walking through the Sun Gate into Machu Picchu itself, which is the reason people pay a premium and book it six to twelve months ahead through a licensed operator, since independent trekking on this specific route is not permitted and daily permit numbers are strictly capped. If those permits are gone or the timeline does not allow for the advance booking, Salkantay and Lares are the two most established alternatives, both ending with a train into Aguas Calientes rather than the Sun Gate approach, and both offering scenery, in Salkantay's case a genuine high mountain pass near a 6,000-meter peak, that some trekkers rate above the Inca Trail itself.
None of these treks should be underestimated on fitness grounds: Salkantay's high pass sits above 4,600 meters, and even the comparatively gentler Lares route involves consecutive days of high-altitude walking that are meaningfully harder than they look on a itinerary PDF. Multi-day trekking without having spent several days acclimatizing beforehand in Cusco and the valley is the most common way a Peru trip goes from memorable to miserable, so treat the acclimatization schedule as a prerequisite for the trek, not a nice-to-have.
Practical details: altitude, money and connectivity
Peru's currency is the sol, and Cusco and the Sacred Valley are cash-friendly but not cash-only; cards are widely accepted in restaurants and larger shops in tourist areas, with cash more useful for markets, small transport, and tips. ATMs in Cusco are plentiful, and withdrawing soles there rather than exchanging money at the airport tends to get a better rate. eSIMs covering Peru are straightforward to set up before arrival and worth it, since connectivity in Aguas Calientes and along trekking routes is patchy at best.
Altitude sickness medication such as acetazolamide (commonly known by the brand name Diamox) is available by prescription and used preventively by many trekkers, worth a conversation with a doctor before departure if the itinerary includes Salkantay or the higher stretches of the Inca Trail. Travel insurance that explicitly covers high-altitude trekking is worth checking for rather than assuming standard policies include it, since some exclude activities above a set elevation. None of this is meant to make the trip sound risky so much as to make clear that Peru rewards a bit of upfront homework far more than a spontaneous, unresearched arrival would.