Reuters Solar Impulse 2 is the first plane to travel around the world powered by the sun

The Solar Impulse 2 plane that's powered entirely by the sun, has completed its historic round-the-world journey.

After leaving Cairo on 23 July, it touched back down in Abu Dhabi where it originally started from in March 2015.

The 17-stage journey covered over 42,000km, crossing four continents, three seas and two oceans.

The team set 19 official flight records during the global adventure, which they used to promote renewable energy.

The pilots said it was an amazing adventure, despite sitting in a freezing cold cockpit for as long as five days and five nights at a time, not having enough room to stretch their arms, have a shower, or even go to the toilet properly.

SIX SOLAR IMPULSE 2 FACTS

Reuters 'Hawaii' nearly their yet?

The longest leg of the journey was an 8,924km flight from Nagoya in Japan to Hawaii in the USA - it lasted nearly 118 hours and broke the absolute world record for the longest solo flight without a break.

Solar stats

The Solar Impulse 2 plane is 72m wide, that's 3.5m wider than a Boeing 747-81 jumbo jet

Getty Images Light as a feather: Solar Impulse 2 had to be light enough to be powered by solar energy

Most planes weigh hundreds of tonnes, but the Solar Impulse only weighs the same as a car

EPA/AMALIE DECLOUX 'I've got more solar panels than you...'

The plane has 17000 solar cells which store the energy of the sun and use it to power the Solar Impulse 2's batteries.

EPA/SOLAR IMPULSE Solar selfie!

The cockpit is only the size of a telephone box. The pilots have to wear oxygen tanks to breathe at high altitude, they're only allowed to only sleep for 20 minutes at a time, and if they have to wee, there's a special hole in the pilot's seat!

Getty Images 'Let me float my next idea past you'