Mercury, toxic to humans, is the only known metallic element that is liquid at standard Earth temperature and pressure and therefore comprises a hazard to children because it is so cool. But many historic human activities have involved the use of mercury, including gold and silver mining, the production of the red pigment vermilion, felt production, and manufacture of mechanical pressure gauges, thermometers and other devices. One guy even made a mercury fountain for the Spanish Pavilion at the 1937 World Exhibition in Paris, now on display at the Fundació Joan Miró in Barcelona.
Click here for original story, Researchers estimate anthropogenic mercury emissions from 1500 to 1900
Source: Phys.org