Sealand was invaded by Germans in the seventies, but the original occupants recaptured it.

The Swiss Guard are trained like our SAS, the pikes are the visible weapons, (those uniforms are very padded, aren't they?) and you never get to see the regiment stationed inside - have you read Dan Brown?...
Oh, and you'd have to invade Italy first, just to get there.

BTW - Welcome Meridius.