Not forever.

Just for say, five seconds?

Would we just hold our breath?

What would happen to the atmosphere?

What would happen to the environment?

This is What If and here's what would happen if the world lost oxygen for just five seconds.

Take a nice deep breath. Feel how satisfying that is?

What you're breathing in is oxygen.

And it takes up roughly 21% of our atmosphere with 78% being nitrogen.

Although it's not the most abundant gas in our atmosphere, it is the most important.

Without oxygen, plants, animals, water and us, humans wouldn't be where we are today.

Five seconds may not sound like a whole lot of time to be without oxygen.

Most of us can go at least 30 seconds without taking a breath, so it would happen too fast for your body to even notice.

Your breathing would actually remain norma, but as for everything else, not so much.

In just five seconds, the earth would look completely different.

Without oxygen, you can say goodbye to the Hoover Dam, the Pantheon Dome and anything else made of concrete.

These structures would instantly collapse.

Oxygen acts as a special binding agent to concrete.

Without it, concrete is just dust.

Speaking of buildings, any untreated metal would instantly be fused together.

This is because there's a layer of oxidation on metals that prevents them from welding together.

Without that layer, metals would instantly bind to each other.

If you happen to be relaxing at the beach at the time, expect a severe sunburn.

The ozone layer, our protection against the sun's UV rays is made of oxygen.

Take away the oxygen and the earth would become extremely dangerous.

There would be nothing protecting us from the sun's UV rays.

In addition to a sunburn, our inner ear would explode.

Losing oxygen means losing 21% of our air pressure.

A change in air pressure that drastic is equivalent to being at sea level and dropping down 2000 meters instantly.

Our ears wouldn't have enough time to adapt.

Having a good time yet? Well, don't expect it to last long.

Without oxygen, there's no fire.

The combustion process in vehicles wouldn't be able to occur.

Any mode of transport that isn't electric will automatically fail.

Planes will fall from the sky and millions of cars will be stopped in their tracks.

The sky would be completely dark.

Before it hits the earth, light from the sun bounces off multiple particles in the air.

Without oxygen in the atmosphere, there are less things to bounce off and the sky will appear dark.

Oh yeah, and while all this is happening, the earth's crust would completely crumble.

That's because Earth's crust is made up of 45% oxygen.

The crust would crumble and continue to crumble until there's nothing left, sending you and everyone on the planet into a free fall.

Sound like fun? Probably not.

But luckily, you can take a deep breath of 21% oxygen, knowing this will never happen.

For more things that are fun to speculate on, keep checking back with What If.