Namibia in south-west Africa is world famous for its hot and sandy Namib Desert and its rugged Atlantic Skeleton Coast.
The last thing you might imagine is that the country also holds clues to the Earth's largest ice age. But it was here, 20 years ago, that geologists first recognised one of the most unusual events in our planet's history: the "Snowball Earth".
In July 2015, I was exploring Namibia with a group of geologists led by Paul Hoffman.
It was Paul and his colleagues who, in the 1990s, discovered the significance of the rocks lying in Namibia's hot, dry desert. He has been back almost every year since to uncover more of Earth's secrets.
The Snowball Earth theory is one scientists once dismissed as ridiculous. It proposes that, over 700 million years ago, the whole planet became so cold that ice spread from the poles all the way to the equator. The Earth was effectively one giant snowball, and remained so for tens of millions of years.
Namibia is not exactly the place you would think to go looking for signs of this ancient snowball age, but it was evidence found in Namibia that confirmed the supposedly impossible idea that the Earth once had ice at the Equator.
The rocks found in Namibia's mountainous deserts were once deposited at the bottom of the ocean. They contain evidence of glacial activity – similar kinds of rocks are forming under the ice-covered Arctic Ocean today – but crucially, they were deposited in the tropics. This showed that ice covered the planet 700 million years ago.
We were there to see these extraordinary glacial deposits, but fieldwork in Namibia is no easy task.
The country is nearly four times the size of the UK and if you are going anywhere off the beaten track you will probably be driving for miles on bumpy dirt roads. Venturing away from any of the tourist areas means taking food, camping equipment, water and several spare tyres with you.
We were headed for a remote region between the Huab and Ugab rivers in north-western Namibia. It is a hot and dry desert landscape, fragmented by spectacular mountain ranges.
The scenery is dotted with dead, skeleton-like trees. Living trees are only found in dried-up river valleys where the roots can reach down to water lurking somewhere deep below. It is here that elephants roam, well aware of where they will find water.
The best way to get around is in a pickup truck, affectionately known as a "bakkie", adapted for camping with a tent on the roof. This means you can stop and camp anywhere you need to.
Evenings are usually spent around a campfire with a guitar, listening to stories about fascinating wildlife encounters or Namibia's extraordinary geology. Mornings are spent bleary-eyed lighting a fire to brew the coffee before an early hike into the hills.
Every night, perfectly clear skies reveal the Milky Way in all its splendour. You can lie out watching it for hours, with more stars than you have ever seen tracking overhead.
One afternoon, we were walking back over the hills after a long day in the field and felt the wind getting up. Down below us, in the valley where our camp was, there was a huge sandstorm building.
We watched as it moved closer and closer to our camp. Eventually it enveloped the camp and we fought our way back through the wind to find broken tents and sand in everything. Our food that evening was a little crunchy.
There are predators lurking around every corner. Unfortunately, outside national parks wildlife is sparse, but we saw many grazing animals and stumbled across many old ostrich nests.
Throughout the whole trip it seemed that the elephants were one step ahead of us, always leaving tracks and fresh dung to tease us but never showing their faces.
There are many weird and wonderful plants in Namibia adapted to the dry conditions, but one in particular deserves a mention: welwitschia. It is a truly unique plant consisting of just two leaves that continue to grow and grow for its whole life.
When I say its whole life, that can be an extraordinarily long time. These small plants live an average of 500 to 600 years, and some have been carbon-dated to over 1000 years old.
There is something special about being out in the wild, not just for the incredible scenery and wildlife, but also because human compassion really shows. In situations where tyres go flat or vehicles run out of fuel, the next person that comes by will always help and never expect anything in return.
We were rewarded by everyone we met, the wildlife around us – and most importantly by the geology, and the evidence it holds of the planet's incredible changing past.
Vivien Cumming is @drvivcumming on Twitter and Instagram