When the Hoover Dam was 
completed in 1936,

it created a huge source of 
hydroelectric power

and zapped a sleepy desert town to life: 
Las Vegas, Nevada.

With the power supply from the dam,

Las Vegas soon exploded 
with vibrant displays.

The source of these dazzling lights was 
electrified neon gas.

There are two tricky obstacles 
to making lighted signs

out of this naturally clear, 
odorless gas:

capturing it and making it glow.

French inventor Georges Claude came up 
with techniques to do both.

In 1902,

he developed a way of liquefying and 
separating specific gases from the air,

producing neon on an industrial 
scale for the first time.

By 1910, he had come up with a way 
to trap the gas in a glass tube

with a special electrode at either end, 
and neon lighting was born.

In workshops like Claude's,

artisans known as tube-benders 
made neon signs by hand.

The tube-benders heated small sections 
of a long, hollow glass tube

and quickly bent them into shape.

After the glass cooled, they attached 
electrodes to each end

and removed the air with a vacuum pump.

Then, they passed a high voltage 
current through the tube

to remove any impurities on the 
inside of the glass.

Finally, they pumped the neon gas in 
and sealed off the electrodes.

When a neon sign is turned on,

the electric current causes some of 
the neon atoms' electrons to accelerate

and break free of their orbits, leaving 
behind positively charged ions.

As these free electrons rush from 
one electrode to the other,

they collide with more neon atoms, 
causing them to ionize as well.

When these excited electrons fall back 
to their normal energy levels,

their excess energy is carried away 
by photons, or particles of light.

All this happens in an instant,

and the glow from the photons is what 
we see when we switch on a neon sign.

Though it's common to call any 
gas-filled sign a "neon" sign,

there are actually 5 different 
gases used in production.

Each gas emits photons of a different 
wavelength when electrified,

which correspond to different 
colors of light.

Neon gives off an orange-red glow, argon 
glows a pale lavender,

helium a dusty pink, krypton a silver-
white, and xenon a light purple.

These 5 gases can be combined 
with color-coated tubing

to create an electrified rainbow of 
text and images.

Business owners soon realized how 
effective these colorful beacons

were for attracting customers.

And unlike a light bulb, a neon sign has 
no incandescent filaments to burn out,

and can shine continuously for 40 years 
before the gas depletes.

By the 1930s, neon signs were lighting 
up storefronts all over the world.

Because of the glass tubes' 
fragile nature,

it usually wasn't feasible to ship 
them over long distances.

Instead, most neon signs were created by 
local neon shops

and then installed nearby.

Signs with humor, personality, and 
intricate designs proliferated,

no two exactly alike.

But by the end of World War II,

plastics had become widely 
available and inexpensive,

and plastic signs supplanted neon 
as messengers of modernity.

Many towns removed neon signs they 
viewed as old-fashioned.

Today, neon sign production is only 
a fraction of what it was at its peak,

but the craft of tube bending lives 
on relatively unchanged.

New creations hand-crafted 
by local artisans

join survivors from the heyday of neon,

hiding in plain sight in city streets 
around the world.