Daring photographer captures rare images of lava lake that's been flowing for over 100 YEARS (3)

'The real problem in Erta Ale is that the crater rim is always changing as the lava lake moves up and down, and especially when it overflows, changing any previous knowledge you might have had about the terrain.

'You might think that the ground you're standing is solid, but equally it might be soft and make you plunge into the lava. You must be very careful.'

Mr Santos used a drone to film his footage from above the lake, alongside four 4K resolution cameras that could handle the scorching conditions around the lake's rim.

He said: 'I needed to be so close to monitor the drone, since the heat waves are so, so strong, they could cause it to melt or crash. I had to be very patient.'

Mr Santos added: 'Every two or three minutes you can hear a small hiss of pressure beneath the volcano and all of a sudden - you can't predict when - a crack just opens wide.

'Then it's like fireworks - the whole volcano starts bursting with lava into the air.'

The Danakil Desert, where the volcano lies, is officially the hottest inhabited place on earth, meaning Mr Santos could only film in the early morning or late at night.

Despite the challenges of filming in such intense heat, Mr Santos is proud to have visited such an epic location on two separate occasions.

He said: 'It's a basaltic shield volcano and there's only six in the world.

'This is one of those that you can actually approach. It's an unbelievable experience.

'It still amazes me how nature works and I think it will continue to amaze me.'

Little is known about Erta Ale, as the surrounding terrain is some of the most inhospitable on Earth, and the natives are said to be hostile towards visitors.

In 2012 a number of tourists were kidnapped, injured and some killed in the area.

Mr Santos explains: 'The volcano is quite close to the border with Eritrea, with whom Ethiopia has a very difficult relationship, as it is known.

'Since then, an Ethiopian military camp site was established nearby and you must now always have a military escort with you while you climb up to the volcano.

'But, at least to me, they were extremely friendly and helpful with finding the most secure places to set up the tripods. They have an excellent knowledge about the terrain.'

In 2009, BBC TV show The Hottest Place On Earth went there to record a world first 3D laser image of the volcano. Durham University earth scientist Dr Dougal Jerram and a team from the BBC explored the surrounding desert.

He later wrote for BBC News: 'Like a true journey to the centre of the Earth, volcanoes provide a unique window into our planet's interior.

'Standing at the lip of the lava lake you can see why the locals see this as "The Gateway to Hell", as the incandescent bubbling lava lake hisses like some badly burned porridge cauldron, overturning and occasionally belching molten lava.'