The passports that open all doors

Crossing international frontiers can involve a tangle of red tape, but some passports and travel documents cut through it all. Here's how diplomats, investigators, leaders and royalty slip through without the hassles experienced by us mere mortals.

(CNN) — Chances are you only have one passport -- maybe two if you have dual nationality.

But find yourself in a particular job -- diplomatic, investigative or even presidential -- and you may get your mitts on documentation that's altogether inaccessible to the hoi polloi.