As I look around this hot and dusty Egyptian desert, orange sand and dry rock formations in every direction, it’s hard to imagine water. But once upon a time, that’s all there was here.

Go back long enough – I’m talking many millions of years – and all of this would have been underwater, covered by a vast sea.

If I was able to time travel 40 million years into the past to the exact spot I’m standing now, I would be on the sandy floor of a sea and, swimming around me, would be prehistoric animals that would become extinct eons before humans appeared.

Rushing past me in the water might be a basilosaurus – a terrifying carnivorous creature that was one of the earliest whales. The basilosaurus was possibly the largest animal that existed in the world back then. 20 metres in size, it had a long slender body and a pointed head with large sharp teeth. And legs.

Yes, you read that correctly. This ancient whale also had legs.

The reason we know this is because this desert in Egypt is home to the most incredible collection of fossilised whale skeletons, gaining it the name ‘Whale Valley’.

The basilosaurus that might have been swimming past me would one day have died and fallen to the seabed. And then another one would have done the same. And another one. 40 million years ago.

Their bodies would slowly have been covered in sediment over thousands of years, keeping the skeletons in place. And then, as tectonic plates continued to move continents around the globe, this part of Africa was pushed upwards and out of the sea.

In the hot dry climate, the fossils were protected in sandstone. Until, just in the past century, humans dug through to find them and discover evidence of one of the great scientific mysteries: Did whales really once walk on land?

Out here in the desert at Whale Valley, I stand in front of one of the fossils. It’s laid out on the sand and my eye traces its outline from the tip of its tail and up to the skull.

The skeleton is so large and positioned on a slight incline that I have to walk alongside it to be able to get a good look at every part.

It’s just one of more than 400 whale skeletons that have been discovered here – and it’s assumed there are many more waiting to be dug up in the future.

Not all of them are on display. For starters, they’ve been found over a large area of land that would be impractical for visitors to see. Also, many of them have ben taken away for scientific research or to be displayed in the world’s museums.

But there are a couple of dozen different groups of skeletons and other discoveries that you can see when you visit Whale Valley.

It’s not just the basilosaurus that you’ll find here. There are also skeletons of another whale from a similar period called the dorudon, which was much smaller at about 5 metres long.

Scientists have also found fossils of other sea animals like turtles, sharks, and crocodiles. This helps them create a picture of what the landscape would have looked like here. There are even fossils of mangrove trees, showing it was probably a shallow sea with bays and islands.

But it’s the basilosaurus that is the highlight here. For a visitor like me, it is the most impressive skeleton you’ll see. And for scientists, it is one of the most important discoveries ever made for the story of evolution.

At the entrance to the Whale Valley site, there’s a small museum. I go inside not expecting much but it actually gives a good overview of the story of the site and there’s a very informative video.

The first thing I see is a pair of legs. Well, the fossilised bones of two legs.

It’s these legs (and all the other ones discovered here) that are the most important thing to be found at Whale Valley.

The fact that the legs were attached to a whale that lived permanently in the sea was quite incredible. It had always been assumed by evolutionists (including Charles Darwin) that whales must have once lived on land because they were mammals. But there had never been any proof.

But here it was. Finally paleontologists had found the missing link in the story and it was the basilosaurus.

In some ways, it’s enough of a reason for tourists to visit Whale Valley. This is one of the most significant things in the (very long) history of the world and I’ve certainly travelled out of my way to see much less.

But it’s the environment that I discover out here that I think offers even more incentive to make the trip. Because the natural landscapes that have been sculptured over millions of years by the receding waters and the winds is spectacular.

The rock formations that come out of the sand create such fascinating shapes – towers and domes, curves and lines. They have layers of different colours, formed by sediment from different eras.

And they all create a warm and textured background for the fossils that are on display here.

Not many people make the trip from Cairo to Whale Valley, even though it’s only about 100 kilometres away. That’s presumably in part because it’s not that simple to get here (which I’ll discuss in a moment).

But it does mean that I almost have the site to myself. There are a few other people here who I pass occasionally or spot in the distance but, for the most part, I am completely by myself as I explore.

There’s a suggested route that takes you through the desert, around the rock formations, and to the different displays with information boards. It’s about four kilometres to walk the whole thing so, with the stops to read the boards and take photos, it takes me at least 90 minutes to go around the site.

I quite enjoy being alone during this period, giving me the chance to think about the significance of what I’m seeing. The bones in front of me are more than just bones – they are a link to the history of the planet. They are a tangible object representing concepts of time and change that are so large and so slow that they are normally impossible to grasp.

Most of the time I spend in Egypt is at the temples, tombs, and other legacies of the Ancient Egyptian Empire. When I’m at those sites, I so often remark how old they are.

Well, these whale bones sure put that into context… by about 40 million years.

How do you get to Whale Valley?

Unfortunately it is not easy to get to Whale Valley independently. The only options are to hire a car and drive yourself there, or go with a tour company.

The road into Whale Valley is quite rough so the tour companies tend to use 4WD vehicles to get you in there, rather than a bus. So almost all of the options are private tours of up to about 4-5 people. That means that it’s cheaper per person if there are more of you. I couldn’t find a tour that I could just join as a solo traveller.

It’s possible to do a tour from the closest city of Fayoum but it’s probably easier just to do it from Cairo, unless you have a particular interest in spending some extra time in Fayoum.

Most of the tour options are pretty similar and do some extra stops like the waterfalls of Wadi El Rayan, maybe sand dune driving, or perhaps the ruins of an ancient Greek city nearby.

I would suggest have a look at this tour, or perhaps this tour, or you could also consider this tour. They are all quite similar and each of them will be cheaper per person if you are travelling in a group.