Photography went from an eight-hour ordeal to a billion pictures a day in under two centuries, and the milestones along the way make superb trivia. Cover the answers, lock in each guess, and keep score — the Windows one is hiding in plain sight.

Which optical trick, described by thinkers in ancient China and Greece, predates photography by more than two thousand years?

The camera obscura — light through a small hole painting an upside-down image on a wall.

How long was the exposure for the oldest surviving photograph, taken by Nicéphore Niépce around 1826?

At least eight hours — and some researchers argue it took days — for one grainy view from his window in France.

Who took what's often called the first selfie — in 1839?

Robert Cornelius, a Philadelphia lamp maker who uncapped the lens, sat for about a minute, and became his own first subject.

Why does an 1838 Daguerre street scene of a busy Paris boulevard show only one visible person?

The minutes-long exposure erased all the moving traffic — only a man standing still to get his boots shined made it into history.

Who coined the word "photography"?

Astronomer John Herschel in 1839 — from Greek for "drawing with light." He later gave us "snapshot" too.

How was the first color photograph made, in 1861?

Physicist James Clerk Maxwell had a tartan ribbon shot three times through red, green, and blue filters, then combined the images.

What does "Kodak" mean?

Nothing — George Eastman invented the word because he liked the strong letter K, then sold it with the 1888 slogan "You press the button, we do the rest."

How capable was the first digital camera, built at Kodak in 1975?

It weighed about 8 pounds, captured 0.01 megapixels, and took 23 seconds to save one image to cassette tape.

Why doesn't anyone smile in 19th-century portraits — was it really the exposure times?

Only partly. By mid-century, exposures were down to seconds; the bigger reason was custom — a photograph was a formal, once-in-a-lifetime document, and grinning was considered foolish.

When was the first photograph taken from space?

1946 — a camera bolted to a captured V-2 rocket snapped Earth from about 65 miles up.

What is "Earthrise"?

Astronaut Bill Anders's 1968 photo of Earth floating above the lunar horizon, taken aboard Apollo 8 — often credited with energizing the environmental movement.

What photographic equipment did Apollo astronauts leave on the Moon?

A dozen Hasselblad cameras — abandoned to save weight for the rocks they carried home. Only the film magazines returned.

What is likely the most-viewed photograph in history?

"Bliss" — the green hill and blue sky of the Windows XP wallpaper, a real, essentially unaltered 1996 photo of a rain-fed hillside in Sonoma County, California.

What is the most expensive photograph ever sold at auction?

Man Ray's "Le Violon d'Ingres" — about $12.4 million in 2022 for a 1924 image of a woman's back painted with violin f-holes.

From eight hours per picture to a wallpaper seen by billions: if you called "Bliss," you've officially recognized the most famous hill on Earth — which you've stared at for years without once asking where it was.