Often when people think of Peru they think of Machu Picchu. There is a good reason: Machu Picchu is an unbelievably gorgeous place. Originally built as a residence for the Inca emperor Pachacuti in the 15th century, the ruins of Machu Picchu lie precariously in the col between Machu Picchu and Huayna Picchu Mountains. The saddle between the mountains drops precipitously to the east and to the west and depending on the weather it can feel like you are floating in a sea of mountains, clouds, or both. The size of the stones in the various structures throughout the site and their trapezoidal shapes are a testament to the immense knowledge of the Inca, as these construction techniques are resistant to seismic activity. However, the site is relatively remote and not accessible by road.
Almost all journeys to Machu Picchu begin in Cusco at 3,399 m (11,152 ft). There are flights from Lima to Cusco, as well as buses from throughout the country. Word of warning: Coming from the coast to Cusco on a bus will bring you up to altitudes much higher than Cusco itself, so prepare yourself by limiting caffeine, alcohol, and sugar before and during the first few days of the trip. Drink lots of water during your trip, and take it easy upon arrival. Only take altitude medications if you are experiencing serious symptoms or if you have experienced them in the past.
Chamomile and coca leaf tea are great natural remedies for the soroche (altitude sickness), but beware that coca tea contains alkaloids that may show up in a drug test for a short while after drinking it. The tea will not intoxicate you in anyway, but you may feel a zing like drinking a coffee or strong black tea.
The ruins of Machu Picchu sit at 2,430 meters above sea level (7,970 feet), while the town of Aguas Calientes, which contains all services: hotels, food, limited medical service, etc., sits at 2,040 m (6,690 ft). There are three main routes to Machu Picchu from Cusco: on one of the trails, by train from Cusco, or the budget route which combines buses, vans and/or cars, and walking (the way I took). View Peru has several packages and Itineraries if you would like to hike one of the trails to Machu Picchu. The train from Cusco is quite pricey, but it offers a one-of-a-kind perspective as you will go where only the tracks go. Part of the year PeruRail offers only a bimodal service, part of the journey on a bus and part on a train, but the rest of the year they offer train service from Cusco to Aguas Calientes. Buying ahead is crucial.
In the end, Machu Picchu is a must-do in Peru, no matter how you arrive. The history, landscapes, and kind people will blow you away at every turn. Once you are standing amidst history you will surely appreciate whatever effort you made to arrive at such a magical, special place.