Carribean = Ca-rib-BEE-an (slight emphasis on 3rd syllable) in UK. US = Cu-RIB-ian as I remember.

I've certainly heard both among US'ns.

if you call the disneyland ride "Pirates of the Cu-RIB-ian", your friends and family will laugh at you . evidently it's an iambic quadrameter (?) thing

Hmm, that would require you to say PY ruts OF the CAIR uh BEE un. I like the swing of PY ruts of the cuh RIB ee un better.