Since a decree of 1805, Paris street numbering has followed a simple rule. On streets parallel to the river, numbers increase in the direction of the current, so from east to west. On perpendicular streets, they start at the Seine end and rise as you move away from it. Even numbers are on the right, odd numbers on the left. With a little practice, a house number tells you which way the river lies.
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.