Krypton was hiding in plain sight

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Perfection can be boring, and so it is with the chemistries of the noble gases. Once argon was discovered 1894, the others were diligently sought and found hiding in liquid air in 1898. First came krypton--its name meaning hidden one--the other two, neon and xenon, were found a few weeks latter. Lord Rayleigh and William Ramsay won the 1904 Nobel Prizes in Physics and Chemistry for their discoveries.
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Helium, the first noble gas, was first found in the solar spectrum, not in thin air.

Neon Rhymes With Helium*

Nothing says periodicity like neon and the other six noble gases. From top to bottom, they shore-up the whole right-hand side of the Periodic Table:

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A noble gas appears at the end of each row like a rhyming element. There are seven complete periods (rows) in the table above. Work has begun on the 8th period.  Don't let the gaps in the table fool you; they are just an artifact of our Cartesian thinking: link.

At the very bottom right of the table is Ununoctium, the last noble gas. Only a few atoms of Uuo have been made, not enough to characterize in detail, but I'm sure that the properties of Uuo would make radon (Rn) look tame. Most transactinide elements are not of this earth.

Back to earth. Neon's colorful history and etymology are covered here by van der Krogt.  The entire noble gas family eluded scientists for decades and for good reason. Interestingly, Neon's name was suggested by its discoverer's 13 year old child.

I think neon signs are cool. I didn't know until today that there's a Museum Of Neon Art (MONA) in Los Angeles link.  I'll have to add it to my list of places to see.

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*The name "Helium" is a bit of misnomer. It should called Helion. The suffix "ium" really and truly belongs to metallic elements. At the time of helium's discovery on the sun, it was assumed that helium was metallic.