An obsession with a single digit

Seven is the world's favorite number.

Ask 44,000 people to name a number and more choose seven than any other. It hides in our weeks, our myths, our rainbows and our fears. Here's why.

The oracle

Draw a secret about seven.

Every tap turns a new card — folklore, taboo, mathematics, the cosmos. There are more here than you'd think.

Folklore Ⅶ · 01

Tap the card to reveal your first secret of seven.

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Seven of sevens

It's everywhere once you look.

7

Days of the week

Named for the seven "wandering stars" the ancients could see in the sky.

7

Colors of the rainbow

Newton chose seven on purpose — to match the seven notes of music.

7

Deadly sins

Pride, greed, lust, envy, gluttony, wrath, and sloth.

7

Wonders

Of the ancient world — only the Great Pyramid of Giza still stands.

7

Seas & continents

Sailors spoke of the seven seas long before any map had them.

7

Notes in the scale

Do, re, mi, fa, sol, la, ti — then it all begins again.

7

Heavens

To be in "seventh heaven" is to reach the highest one of all.

7

Neck bones

You and a giraffe share this: almost every mammal has seven.

The forbidden & the strange

Where seven turns uncanny.

The unbuildable shape

A perfect seven-sided polygon can't be drawn with only a compass and straightedge — the heptagon is the smallest regular shape that's simply impossible to construct that way.

Seven years' bad luck

Break a mirror and the curse lasts seven years — the Romans thought the body renewed every seven, so a shattered reflection wrecked a whole cycle of the self.

The number that repeats

Divide 1 by 7 and you get 0.142857… forever. Multiply 142857 by 2, 3, 4, 5, or 6 and the very same digits reappear, just rotated. Mathematicians call it cyclic.