Back in 1852, aluminium was nearly twice the price of gold, trading at $34 per ounce compared to gold's $19 per ounce.
Then, in 1886, two young inventors, Hall in the US and Héroult in France, each found a way to produce aluminium on a large scale. Nowadays, aluminium costs just $0.01 per ounce, while gold is priced at $3,400 per ounce.