Ever try to explain the concept of countries and continents to your students and gotten nowhere? Perhaps this 5 minute video will help. It shows the changing borders of the different countries that have existed in Europe over the last 1,000 years.
Notice that while the borders drastically change, the continent stays the same:
Hopefully that helps?
Hat Tip to Duffy at Colossus of Rhodey (see blogroll) for that one.
"If a nation expects to be ignorant and free... it expects what never was, and never will be." -Thomas Jefferson