Saqsayhuaman (pronounced säksäwämän) was built by the Inca empire as one of 4 temples surrounding the city of Cuzco, Peru. Started in 1431, it took 77 years (finished in 1508) and thousands of workers to complete. At the time, one estimate was that the number peaked at 30,000 workers at one time.
The temple was constructed out of huge, immensely heavy cyclopean blocks, which were hauled up the mountains (a total height of 3555 meters above sea level), without aid of wheeled vehicles. Once the blocks were at their destination, they were hoisted up and set in place. No fillings were used at all; such was the precision of the Incas work. At its completion, Saqsayhuaman was over a third of a mile long and had 3 huge terraces. It was so big that many years later, it was mistaken for a fort instead of a temple.
"...many of them are so fitted that the joint hardly shows, and to think how they could fit stones so immense so well that you can scarcely insert the point of a knife between them..."
Inca Garcilaso de la Vega, born 1539
In 1536, Manco Capac laid siege to the city of Cuzco, occupying Saqsayhuaman for 10 months, until the siege was called off, but not before leaving Cuzco in near ruin. For several years from 1559, the ruins of Saqsayhuaman were mined to help rebuild Cuzco.
In modern times, Saqsayhuaman is now a popular tourist destination within Peru, attracting thousands of people each year who marvel at its sheer size, as well as the ruins of the city of Cuzco.
Note: While researching, 4 different spellings were found, being Saqsayhuaman, Saxsayhuaman, Sacsayhuaman and Sacsahuamán. Saqsayhuaman was chosen as it already existed as a nodeshell