There are 51 countries and independent states in Europe, although politics in some areas cause people to believe this number should be different. The countries in Europe with the most people are Russia, Germany, Great Britain and France. People from Europe migrated to Australia in large numbers from the 1800s onwards, resulting in millions of Australians now having ancestors who lived somewhere in Europe. What is a continent, and are there seven or five? Some continents are surrounded by water, but others have borders with each other that are often difficult to define. Did you know that the continents can move? How does this happen and what does it mean for the future of the continent you live on? Find out all about Earth's continents, how they are similar and how they differ, as well as the effect people have had on the landscapes where they live.