As you read this, countless cards, letters and packages are en route to delivery destinations across the globe. We rarely think about the logistics involved in international mail crossing land and sea, country borders and continents, because we don't have to. We simply take our item to the nearest postal service branch, pay an acceptable conveyance fee, and within a week or sooner, that item can end up on the other side of the world. But some two hundred years ago, eccentric minds were devising ways of cutting international delivery times to hours or even minutes. Their method? Rockets.