If the city of Cuzco is considered to be in the shape of a puma, then the mighty fortress of Sacsayhuaman would be located at the head, and its sharply zig-zagged outer walls could represent the fierce teeth of the animal. Sacsayhuaman figured prominently during the Spanish Conquest, with a fierce battle taking place there between conquistadors and natives during the Great Rebellion of 1536.

The fortress-temple of Sacsayhuaman (meaning "satisfied falcon") lies immediately above Cuzco and was primarily protected by three massive terraced walls, rising over sixty feet and built in a zig-zag fashion in order to break up attacking forces. Within the terraced walls were three huge towers, the largest of which had a rectangular base sixty-five feet long and rising up five storeys. It could comfortably house over 5,000 soldiers and was described by later Spanish historians as having "too many rooms and towers for one person to visit them all". Sacsahuaman was built as more than a military fortress - the entire population of the unwalled city of Cuzco could have retreated within it during times of war.

Modern-day Sacsayhuaman is a poor comparison, with only a portion of the defending outer walls and the foundations of the three main towers remaining. The conquistadors deliberately destroyed most of the fortress by 1560, though eyewitnesses before that time claimed that it would have ranked as one of the wonders of the world. One great stone remaining in the outer wall is 8.5 metres high and estimated to weigh over 360 tons.