Salt is an important player in the culinary world but it is also critical to the technology world. 

Across the salt flats of Chile, there are huge deposits of lithium. Lithium was once an obscure member of the Periodic Table.

Then in 1991 Sony introduced the first lithium batteries into its electronic devices. Now it’s used everywhere. Smartphones, tablets, you name it.

Lithium is relatively light and perfect for use in small batteries. So where does it come from? The main source is located at the driest place on Earth, the Atacama desert in northern Chile.

Over the millennia lakes in that region have evaporated, leaving behind a thick layer of salts, including lithium. The BBC’s Gideon Long takes a look.