Aubrey holes

The thing I learned today is that Aubrey holes, named after a 17th-century antiquarian, are 56 cremation pits that line the inside ring of Stonehenge. It is possible that their placement was used for astronomic calculations.

Axel Paulsen

The thing I learned today is that ice skating's move the Axel jump is not named for the rotating axle, as I always thought, but a 19th-century Norwegian speed skater, Axel Paulsen, who invented it.  Who knew?  Lots of people, certainly.

Delaware's nickname

The thing I learned today is that Delaware's motto is "Liberty and Independence," but its nickname is "The First State," which is printed on their license plates. (It was the first of the original 13 colonies to ratify the Constitution.)

Delaware
is well aware
it was the first state

John O'Groats

The thing I learned today is that John O'Groats is a village on the northeast coast of Scotland.  It is mentioned in the phrase "from Land's End to John O'Groats," meaning a great distance, as the distance between those two towns (875 miles) is the longest distance between two inhabited points in the UK.  It is named for Jan de Groote, a Dutchman who settled there.

Mashgiach

The thing I learned today is that a mashgiach (from the Hebrew for "supervisor") is a Jew who oversees a food-service establishment to ensure it is keeping with kashrut, or kosher, dietary laws, and that nothing is trayf, or forbidden.

Size of the Sahara Desert

The thing I learned today is that the Sahara Desert is 3.6 million square miles in area, which means it is nearly as large as the United States or China (both around 3.7 million square miles).

The first St. Patrick's Day parade

The thing I learned today is that the first St. Patrick's Day parade in America was held in Boston, 1737. It was organized by the Charitable Irish Society of Boston.