Radiograph of Nautilus Shell

Though it’s not a perfect golden spiral, the chambered nautilus shells (of both the extant and extinct species) are some of the finest natural examples of a logarithmic spiral.

Build thee more stately mansions, O my soul,

As the swift seasons roll!

Leave thy low-vaulted past!

Let each new temple, nobler than the last,

Shut thee from heaven with a dome more vast,

Till thou at length art free,

Leaving thine outgrown shell by life’s unresting sea!

- Oliver Wendell Holmes

On Growth and Form. D’Arcy Wentworth Thompson, 1945