Why did it take so long to invent the wheelbarrow? Have we hit peak innovation? What our list reveals about imagination, optimism, and the nature of progress.

Source: The 50 Greatest Breakthroughs Since the Wheel – The Atlantic

A few years old, but still interesting. For example:

By expanding the pool of potentially literate people, the adoption of corrective lenses may have amounted to the largest onetime IQ boost in history.