Upon entering the main ruins you'll cross over a dry moat and come across the first site of major interest, the Temple of the Sun. Once used as a solar observatory, this unique complex is the only round building at Machu Picchu. At sunrise during the summer solstice, the sun's rays flood through the window and illuminate the tower with a precision only the Incas could have executed. Also known as the Torre├│n (meaning fortified tower), the temple presents a spectacular, semicircular wall and carved steps that fit seamlessly into the existing surface of a natural boulder, forming some sort of altar. Although access inside the temple is not permitted, the outside architecture is spectacular in and of itself. The temple displays some of Machu Picchu's most superb stonework, and has a window from which the June solstice sunrise and constellation of Pleides can be observed. In Andean culture the Pleiades continues to be an important astronomical symbol, and the locals use the constellation to calculate the arrival of the rains and to determine the best time of year to plant crops. Next to the Temple of the Sun is the Chamber of the Princess, and below the temple is The Royal Tomb.
Machu Picchu and the Inca Trail, Peru