This is so true, a significant percentage of Americans do not have a passport and will never leave the USA. Americans are also very insular in their view of the world. America is the civilised world, so who cares about the rest of the world or where it is?
However, I'm sure the same can be said for many British people too, sure they might know where the Costa del Sol or Costa Blanca are, but If you asked them to show you on a map where countries such as Bolivia, Taiwan, Madagascar, Guyana, Western Sahara, Slovenia or the Philippines were, I doubt many would even get the continent right.
From an early age I've always taken a keen interest in places, countries, geography and have spent many hours studying maps and reading about far flung places, which is probably why I spend so much of my time travelling or dreaming of going to places the average Brit would never consider going to.