For centuries Machu Picchu, the last Inca city, was forgotten until Hiram Bingham, a Professor from Yale rediscovered it and written of it in his book "The Lost City Of The Incas".
Hiram in fact, did not search for Machu Picchu, he was looking for a city the incas escaped to after the Spanish conquistadors arrived in 15th century, called Vilcabamba.
Almost completely encircled by the Urubamba river, the beauty of the city comes from its deep rooted foundations, with a spectacular view of the nature adopted the city buildings over the centuries.
If you search for an irregular experience, Ayahuasca rituals are handled within its peaks by Shaman monks. People that have gone through the ritual have said it is an experience beyond words, having spiritual revelations regarding who they are, and who they were, and at the mountain peak, it is truly amazing.
I consumed it too, and it was the most odd feeling I had, going back to the man I was before this time. Living in a renaissance city I do not identify for a full day. The experience taught me a lot about myself on a journey to discover who I am.