This entry in today’s “Writer’s Almanac” astounded me.

On this day in 1902, archaeologist Valerios Stais discovered the Antikythera mechanism, an ancient analog computer from the first or second century B.C., that was used to calculate the position of the sun, moon, and stars in relationship to the observer’s position on the surface of the earth. For many decades, archaeologists did not recognize the mechanism’s degree of mechanical sophistication, which is comparable to a 19th-century Swiss clock. To date, the only other artifacts with that degree of mechanical sophistication have come from the 14th century or later.

Stais uncovered the mechanism while exploring the Anitkythera shipwreck off the northwest coast of Crete. Today the mechanism is on display at the National Archaeological Museum of Athens.