Ancient History

Quipu: How 132 Cords Matched a 1670 Spanish Census

The Inca ran an empire of millions using knotted cords instead of an alphabet. In 2016 a Harvard undergrad matched six of them to a 1670 census, name for name.

Mutually Assured Destruction: An Insult That Became Policy

MAD was coined in 1962 as an insult, and the doctrine nearly failed twice, in 1962 and 1983, with Arkhipov helping defuse a torpedo crisis and Petrov recognizing a false missile alert.

Mayan Numeral System: Its Zero Predates the Oldest Maya Date

The Mayan numeral system's zero is usually credited to the Maya. The oldest confirmed example is from an earlier culture, predating confirmed Maya use by roughly two centuries.