These are not clocks with decoration added. They are astronomical instruments that happen to display the hour, built when the position of the sun and moon mattered to planting, sailing…
An aqueduct is mostly invisible. The famous arched bridges are the short sections where a valley had to be crossed; the great majority of any system ran underground or along…
Source: Wikipedia
There is a limit to how loud a sound can be, and it is lower than most people assume.
Sound travels as alternating regions of higher and lower air…
Source: Wikipedia
Ask anyone to picture an aircraft black box and they will picture something black. It is one of the most widely held misconceptions about aviation, and it is wrong…
Source: Wikipedia
Most people assume Pompeii has been fully uncovered. The photographs suggest a complete Roman town sitting in the open, streets and houses and shopfronts, waiting for visitors.
Roughly two-thirds…
Mortar is the least glamorous part of any building and frequently the part that determines whether it survives. Stone and brick last for millennia on their own; what usually fails…