mc5 - King AVMA the III

A hospital?

[R] Not a hospital

Is it a 'station' of some kind?

[SM] If it was then it isn’t anymore

Unique?

[CdM] By far the less deceptive answer is yes

Is it below the Earth's crust?

[T] Above the Earth's crust. Unless viewed from its antipodal point, of course, but let's not worry about that kind of pedantry.

Is it outside the UK?

[SM] Yes! Not in the UK.
Also, was probably a bit hedged with the station question. It was (part of) a ‘station’ of some kind.

Is it in Antarctica?