Where did all these lakes come from? Tens of thousands of years ago, huge sheets of ice (called glaciers) covered Finland. As the ice slowly moved, it scraped and dug out hollows in the rock underneath. When the ice finally melted, the hollows filled with water - and Finland's lakes were born.
The biggest lake in Finland is called Saimaa. It is so huge and bendy that it has 14,000 islands of its own inside it. You can travel for days by boat across Saimaa, going from island to island, and not see the same place twice. From above, it looks like blue lace stitched across the land.
Lakes are part of everyday Finnish life. In summer, families swim, paddle and fish in them. Most lakes are clean enough to drink from. In winter, they freeze so solid you can drive a car across them, and children skate and play ice hockey on the surface.
Many Finnish families have a small wooden 'mökki' - a summer cottage - by a lake. They go there to slow down, swim, pick berries, and sit quietly on a wooden jetty looking at the water. The mökki is so important to Finnish culture that there is a national holiday called 'Mökkipäivä' (Cottage Day) every July.