On a modern world map spread out in the centre of the classroom, lay out basic products on the relevant countries of the world that provide Europe with things it can't grow or produce for itself - coffee, tea, sugar, spices etc. Discuss why they might come from the countries they do.
Spread out a world map from a previous century showing the extent of European imperial expansion and lay out the imported products of the time and their place of origin. Pose such questions as why did European countries take-over other countries in the past? What products are still imported to Europe from the same places today? If these countries are now independent why do they still import their goods to Europe? Do they get a fair price for them?