On March 30, 1848, Niagara Falls Ran Dry, with bonus Niagara Falls sketch by Abbott & Costello and The Three Stooges.
Before computers: Inside the FBI’s Colossal Fingerprint Factory.
In this 2.5 minute video, Carl Sagan lucidly explains how Eratosthenes not only deduced a spherical earth, but accurately calculated its diameter in 200 B.C.
For Van Gogh’s birthday, his recently-discovered sketchbooks and the unexpected math behind "Starry Night"
ICYMI, Friday's links are here, and include the history and calculations behind Easter's varying dates, a gallery of Easter bunnies terrifying children, and a collection of videos of violence against marshmallow peeps.