The world’s most extreme railway is in the Sahara Desert

Rare footage of a remote transit line dubbed 'the world's most extreme railway' has been released, and it looks like something straight out of a Mad Max film.

Deep within the Sahara Desert is the Mauritania Railway, a line that sees impossibly long 2.9-kilometre trains embark on journeys that last up to 54 hours.

The railway has been operating since 1963, and National Geographic have just released a stunning short film showcasing the rickety journey.

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As seen in the footage above, over 22 tonnes of iron ore – the nation's biggest export – are loaded onto the train for one trip, and sometimes humans climb on board, too.

It's surreal to see in action, the mammoth train seemingly stretching on forever, and will have you wondering how it's even possible to move such a heavy and spread-out load.

The railway is the only way to get across the desert, and for lots of Mauritanians it is the only option they have to reach distant places, see family, or to find work.

Unfortunately, it also happens to be one of the toughest journeys in the world. Suffocating dust storms, temperatures exceeding 40°C, wild winds and only iron ore to grip on to when things get rough are what comes with this free one-way ticket.

People who live along the railway's path rely on merchants on board the train for the basics of survival such as water, fuel, and staples that are delivered when the train passes their homes.

For the full documentary, visit video.nationalgeographic.com.