Vegemite was invented in 1922 in Melbourne. A man called Cyril Callister was asked to make something useful out of the leftover yeast from breweries. He turned it into a thick, salty paste packed with vitamins. Soon almost every Australian home had a black jar with a red lid in the cupboard.
The trick with Vegemite is the amount. Spread a tiny scrape on warm, buttered toast and it tastes savoury and rich, a bit like a roasted broth. Spread it like jam - which most non-Australians try the first time - and your face will tell the story. Aussie parents teach their kids the 'thin layer rule' early.
Vegemite is so much part of Australian life that it shows up in pop songs, school lunchboxes, and care packages sent to Aussies living overseas. The 'Vegemite kid' - a child grinning with a piece of toast - has been on TV adverts for decades.
Other countries have their own salty yeast spreads too. In the UK, it's Marmite. In Switzerland, it's Cenovis. In each country, kids grow up tasting their own version and being a bit puzzled by everyone else's. Yeast spreads are one of those things almost every country has, in their own flavour.