[NickInSF]

I'm surprised people aren't bringing up the "original" Sphere. Vegas had an Omnimax dome 45 years ago! I have fond memories of it as a kid. The entire theater was comprised of speakers on which spherical movies were projected. It's a shame it never got more traction.

https://en.wikipedia.org/wiki/IMAX#Dome_and_Omnimax

[EvanAnderson]

There's an operating Omnimax dome at the Cincinnati Museum Center at Union Terminal. I don't know how it compares to The Sphere but if you're close by it's worth the trip in my opinion.