Often wrongly mentioned as the Lost City of the Incas, Machu Picchu is the most familiar icon of Inca Civilization, built around 1450 AD, as a summer retreat for the Inca Emperor Pachacuti. In the Quechua language, the term Machu Picchu stands for the ‘Old Peak’. In fact, almost hidden in the Peruvian Andes high on a steep mountain with a flattened top, Machu Picchu escaped the notice of the Spanish conquistadors and was forgotten for centuries by the outside world. The world became aware about its hidden secrets only in 1911, when it was rediscovered by Hiram Bingham, an American archeologist.

Located in the Eastern Cordillera of southern Peru, at an elevation of 7970 feet (2,430 m) above sea level, Machu Picchu is a 15th-century Inca citadel, situated on a mountain ridge above the beautiful Sacred Valley. Built in the classical Inca style, with high walls of massive polished stones, it was constructed around 1450 and is believed to have supported around 750 residents, during the summer months. Held up by a mammoth network of strong underground walls, this unique summer retreat of the Emperor is a planned patchwork of houses and temples. The long stretch of terraced farms notched into the Andean mountainsides used to provide plenty of food to the settlement.

Machu Picchu was constructed atop two fault lines. It is said that, during an earthquake, the stones in an Inca building ‘dance’ and they bounce through the tremors and then fall back into place. If this unique method of construction was not followed, many of the best known buildings at Machu Picchu would have collapsed long ago.

The site is roughly divided into two parts. The people of lower status used to live in the popular district or the residential district, which also included the storage buildings, while the royalty area was the sector for the nobility, consisting of a group of houses located in rows over a slope.

The primary archaeological treasures, consisting of the Intihuatana stone, the Temple of the Sun and the Room of the Three Windows, are located in the first zone.

In English, the Intihuatana stone is often expressed as the ‘Hitching Post of the Sun’ or the ‘Place to tie up the Sun’. The stone was considered as the supremely sacred object by the Inca people and they believed that the stone held the sun in its place along its annual path in the sky. According to the Shamanic legends, if a pious person touches his forehead to the Intihuatana stone, the stone opens his vision to the spirit of the world. In fact, the stone is a precise indicator of the date of the two equinoxes and other significant celestial periods. It is a uniquely preserved ceremonial sundial consisting of a wide pillar and pedestal that were carved as a single unit and stand 6 feet (1.8 m) tall. On 11 November and 30 January, the sun stands almost exactly above the pillar at midday, without casting any shadow. It casts the longest shadow on its southern side on 21 June, while on 21 December a much shorter shadow on its northern side.

The Temple of the Sun is a semicircular construction, built over a strong inclined rock mass with a small grotto. It was a restricted place and the entrance had a double wooden door secured with a safety mechanism stone ring. The exact location of the citadel was chosen carefully to build it at the highest altitude possible, to watch the sky more closely.

The Temple of the Three Windows stands near the southwestern corner of the Main Plaza. It is a 35 feet (10.6 m) long and 14 feet (4.2 m) wide stone hall , with three trapezoidal windows on one wall, built of polygonal stones, which is believed to be the largest known in Inca architecture. The three windows represent the windows of the three world - the underground (Uku-Pacha), the heaven (Hanan-Pacha), and the present or the actual time (Kay-Pacha). It is believed that they also represent the rise of the sun, the most important event in the everyday life of the Inca people.

Today, two thousand feet above the rumbling Urubamba River, the cloud shrouded the enigmatic ruins of Machu Picchu, which consist around 150 private houses, apart from the palaces, storage rooms, baths and temples - all in a remarkably romantic state of preservation. Strangely, the entire city was constructed with smooth and massive stones, which were interlocked without the use of any mortar. It is a wonder, as to how the ancient Incas moved those massive stones to such a remote location and hoist them without the help of any wheel.

It is not specifically known as to why Macchu Pichu was abandoned. However, scarcity of water may have been a factor. Nevertheless, with its romantic mystery and magical attraction, Machhu Picchu is considered as the most-visited tourist attraction of Peru.   In 1981, it was declared a Peruvian Historical Sanctuary and was enlisted in the UNESCO World Heritage Site in 1983. Further, in a worldwide Internet poll in 2007, it was voted one of the New Seven Wonders of the World.