Some clocks, like those on ovens or clock radios, don't keep time on their own: they count the cycles of the power grid's 50-hertz frequency. In early 2018, a dispute between Kosovo and Serbia over the management of their grid left a persistent electricity shortfall on the continental European network. The frequency stayed slightly too low for weeks, and those clocks drifted almost six minutes behind. Grid operators later made up the difference.
That's the estimate from a WHO-led study published in The Lancet in 2024, covering the half-century since the Expanded Programme on Immunization was launched in 1974. It works out to about six lives saved every minute, mostly infants. The measles vaccine alone accounts for around 60% of those lives.
According to the World Gold Council, about 216,000 tonnes of gold have been mined in all of human history. Because gold is so dense (19.3 tonnes per cubic metre), it would fit in a cube about 22 metres on each side, roughly the height of a seven-storey building. Strikingly, about two-thirds of it has been mined since 1950.