What happens is that the wind blows the sand up the shallow slope on the other side, and then, as each sand grain hits the top of the ridge, it cascades down on the inside of the crescent, and so the whole horn shaped dune moves.

If you want to stop a sand dune from moving, what you need to make sure to do is to stop the grains from avalanching over its crest.

Magnus Larsson Turning dunes into architecture

The desert is there, sand dunes, some small field.

Some of those grains may then accumulate on a massive scale, into a sand dune.

And when you go to the beach, what do you get? You get sand dunes.

We then pull the piles up through the dune and we're able to create almost any conceivable shape inside of the sand with the sand acting as a mold as we go up.

So let's make architectural sand dunes and a beach cabana.

The beautiful thing is that it moves bodily.

There's hundreds, up to a 1,000 or 1,200 miles of dunes.

Inside of the dunes we find shade.

It's obviously a place which is very dry, or you wouldn't get dunes.

It adds roughness to the dune's surface, to the texture of the dune's surface, binding the grains.

Sand dunes are almost like ready made buildings in a way.

So they went out and they modeled a computer model of a sand dune.

It says, well, there's the sea, there are dunes, and I'm here.

The dunes here move southward at a pace of around 600 meters a year.

As I said earlier, it looked very much like Earth, so you see sand dunes.

Now, sand dunes cover only about one fifth of our deserts.

So, we have a way of turning sand into sandstone, and then creating these habitable spaces inside of the desert dunes.

So, we pushed the piles down through the dune, and we create an initial bacterial surface.

In a desert plain in Tanzania, in the shadow of the volcano Ol Donyo Lengai, there's a dune made of volcanic ash.

They love Namibia for its beautiful dunes, that are even taller than the Empire State Building.

But, by now, you're probably asking, how am I planning to solidify a sand dune?

It retains its crescent shape and moves in the direction of the horns.

It's what's technically known as a barchan, and the entire dune walks across the desert in a westerly direction at a speed of about 17 meters per year.

Where were they? It got even more puzzling when we found dunes.

Other activities are taking place in areas such as sand dune fixation, forest management and the promotion of agroforestry.

But what is enveloping Machu Picchu from below?

They had to move this village in 1987 as a huge dune threatened to swallow it.

They took photographs, they fed the photographs into their computer program, and that computer program shaped a sand dune and then took that sand dune shape and turned it into at their instructions, using standard software with slight modifications a set of instructions for pieces of wood.

Machu Picchu was never a lost city.

It provides a physical support structure for the trees, and it creates physical spaces, habitable spaces inside of the sand dunes.

The development of agriculture in hillsides, edges of the rivers and dunes provokes erosion destroying the ground, and reducing land fertility, which harm women the most.

The Asian TPN 3 on rangeland management in arid areas, including the fixation of shifting sand dunes, was launched in 2001.

OK, so this is our movie of the equatorial region of Titan, showing these dunes. These are dunes that are 100 meters tall, separated by a few kilometers, and they go on for miles and miles and miles.

It took us about 10 minutes to climb up to the top of that dune, which goes to show why they had to move to a safer location.

According to the reports, soil conservation continues to be given high priority by the organizations in their efforts to preserve the environment, alongside sand dune fixation strategies.

But, if I had something like a TED wish, it would be to actually get it built, to start building this habitable wall, this very, very long, but very narrow city in the desert, built into the dunescape itself.

The school is on top of the hill.

I went to see the movie Dune, and a girl talked to me. Now, on its face this is impossible on its face, I realize but it is absolutely true.

The children ran down the hill.

The river's on the other side of the hill.

Defensive barriers would not necessarily require heavy investment they could be mounds of sand several meters high located along and near the shoreline. In fact, in some areas of the US and other countries, only extensive dune fields and vegetated areas are used to separate buildings from the seashore.

Adam Ostrow Hello.