In the early 16th century, in Joachimsthal ('Joachim's valley'), now Jáchymov in the Czech Republic, large coins were struck from the silver of nearby mines. They were called 'Joachimsthaler', soon shortened to 'thaler'. The name spread across Europe, becoming 'daalder' in Dutch and then 'dollar' in English. In the American colonies it was used for Spanish pieces of eight, before becoming the official currency of the United States in 1792.
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.