50 greatest innovations since the wheel

The Atlantic asked a group of historians, scientists, and engineers to rank the 50 greatest innovations since the invention of the wheel. Here they are.

21. Nuclear fission, 1939
Gave humans new power for destruction, and creation

22. The green revolution, mid-20th century
Combining technologies like synthetic fertilizers (No. 11) and scientific plant breeding (No. 38) hugely increased the world’s food output. Norman Borlaug, the agricultural economist who devised this approach, has been credited with saving more than 1 billion people from starvation.

23. The sextant, 1757
It made maps out of stars.

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