Sand in Altyn-Emel National Park (Kazakhstan) emits strange, melodious sounds. Scientists have yet to find the exact cause of this unique phenomenon.

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This singing sand hill is 150m high and 3km long.

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When the weather was dry, the sand began to speak.Singing is not continuous.Each lesson only lasts a few minutes.

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The sound is quite similar to cello or bassoon.

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The best way to hear the sand is to climb to the top of the hill and slide down.At that time, sand broke out and a strange sound began to sound.

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Scientists believe that this noise is from the flow of sand created when moving.

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In fact, the sound emitted by sand grains rubbed against each other.

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A wave rolls over the hill, moves sand grains along the way and creates a mysterious sound.

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Singing sand dunes are just one of many interesting attractions in Altyn-Emel, a national park 4 times larger than Hong Kong.

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The 155km Sharyn Gorge is dubbed the "brother of the Grand Canyon".

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More than 260 species of animals live here, from buzzard to beaver.

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Here, paleontologists discovered many animal fossils, from rhinos to ancient turtles, many of which are millions of years old.However, the most mysterious thing in Altyn-Emel is the sand hill that sings.