In fact, the superstructure is estimated to hold an almost inconceivable 200 quadrillion (that's 200 followed by 15 zeros) ...

The Incas had a system of accounting that relied on the quipu. Cords of various colours were attached to a main cord with knots. The number and position of knots as well as the colour of each cord ...

from architecture to knotted quipu, to create a city that ruled the largest Indigenous empire in the Americas, starting with Manco Capac and the successive Sapa Inca rulers. #ExtraHistory # ...