As the legend goes, Manco Capac and Mama Oclla emerged from the sacred lake to found Cuzco and the Inca empire.
If we can suggest you an itinerary, after your visit to Cuzco and Machu Picchu, get the train to Puno (via Juliaca) on the shores of lake Titicaca, it offers one of the most interesting cultures of Peru.
The gateway to the lake (on the Peruvian side) is Puno, considered to be Peru's folklore center.
In fact, they celebrate here more than 300 dances annually. Hardly a day will go past without a dance to celebrate something.
Virgin of Candelaria's celebration and the Diablada (Devil dance) is just fantastic, with a profusion of incredible (and costly) masks, sumptuous costumes and ornamentation.
Diablada was born with the legend of some miners trapped in the collapse of a mine.
They saw an army of demons that took them to hell, but they commended to the Virgin and were rescued.
On lake Titicaca you have several interesting and unique places to travel to...
The floating islands of the Uros people:
Uros people live over 40 floating reeds islands maintained by continually adding fresh reeds to the top as the bottom rots away.
They fled onto the lake about 500 years ago, trying to escape Inca and Collas tribes.
An estimated number of 400 Uros people are part of this floating community. They live in reed huts and travel in reed boats - built upon the same craftsmanship as centuries ago
Taquile Island:
Located about 4 hours by boat from Puno, it's a place with no roads, no cars, electricity or hotels.
Just beautiful landscapes and archaeological ruins. You could spend the night staying with locals or camp on the far side of the island.
With an outstanding textile industry, Taquile it's been proclaimed in 2005 a new Oral and Intangible Heritage of Humanity by UNESCO
Amantani:
The island of the Kantuta flower.
It has important archaeological remains from the Inca and Tiahuanaco's cultures on top of its main mountain peaks: Pachatata (Father Earth) and Pachamama (Mother Earth).
Here also you'll be invited to share their housing and food as the local population - mainly Aymaras - are very friendly and welcoming.
Bring some goods as a present with you.
To get there just get a craft from Puno
Natural Reserve of Titicaca:
A paradise for eco travellers and bird-watchers, founded in 1978.
It has more than 60 species of both resident and migratory birds, like zambullidor, yanuico, cormoran and totorero
By Lake:
From Puno, as well as from Juli and Yunguyo you can navigate Titicaca to/from Bolivian ports.
This is a unique and unforgettable experience you shouldn't miss.