On July 16, 1945, the atomic age began with the Trinity nuclear test. Related, this 1954 PSA, How a Clean, Tidy Home Can Help You Survive the Atomic Bomb, and a rather naively optimistic 1957 Disney classroom film — Our Friend the Atom.
An experimental pneumatic subway secretly built in Manhattan in the late 19th century.
The Physics of How Lawn Mower Blades Cut Grass (at 50K frames per second).
The Torturous History of the Treadmill — it was originally designed to exploit prison labor.
Gallery: The serious side of historical games.
ICYMI, most recent links are here, and include poorly translated English language T-shirts spotted in Asia, that time America air-dropped pianos for troops in battlefields, the evolution of the Army helmet, and the eating habits of Medieval peasants.