Did Neolithic humans build this structure to celebrate Pi Day? Not likely. Pi Day is a relatively recent phenomenon—invented by a physicist in 1988 and designated by Congress a national holiday in 2009. But it"s already almost certainly the most popular holiday celebrating a mathematical constant. While Pi Day is a young tradition, the number π (pi) itself has been a fascination since antiquity, when it was first calculated as the ratio of a circle"s circumference to its diameter.
Pi Day
Today in History
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Indigenous living
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Who created the Easter Bunny?
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Feature Attraction: 85 years at the drive-in
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Rosa Parks Day
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A glimpse of the Blue Forest
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A willowy welcome to spring
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The desert blooms
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A goldie gala
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Keyholes to the kingdom
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Celebrating Pi Day
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World Wildlife Conservation Day
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A river runs through rice fields
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Happy New Year!
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Pretty in pink, and purple, and red…
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World-class art comes to Arkansas
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Sea Otter Awareness Week
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Watson Lake in Granite Dells, Arizona
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National Gardening Week
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Winter solstice
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Scotts Bluff National Monument, Gering, Nebraska
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US Election Day
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Harvest season begins
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