The Llama, the Incas, Perú and the Andes
by Charles Young and Karl Klooster

The Inca Empire
continued)

The single largest edifice ever built by the Incas was the great fortress (pucará) at Cuzco, called Sacsahuamán. This marvel of construction was so large all of Cuzco's 100,000-plus inhabitants could have taken refuge in it.

Sacsahuamán sat on a hill 600 feet above the city. It was nearly a third of a mile long, and consisted of three, giant walled tiers constructed in a zigzag pattern to maximize defensibility. The lower stones were 25-feet high and weighed up to 75 tons.

In all, more than 200,000 huge stones made up the fortress, all lifted and fitted by the human power of 25-30,000 workers over some 50 years.