24 hours is what I grew up with, but it doesn't really matter to me.
Fun fact for the 12h users though; when we speak about the clock, at least here in Sweden, we don't say "See you at 17 o' clock!", we say "See you at five o' clock!".
Fun fact for the 12h users though; when we speak about the clock, at least here in Sweden, we don't say "See you at 17 o' clock!", we say "See you at five o' clock!".