A bog is a type of wetland where plants decompose very slowly because the soil is so acidic. Over thousands of years, layer upon layer of dead plant material builds up into a spongy mat called peat. Walking on a healthy bog feels a bit like bouncing on a very firm mattress.
Estonia's most famous bog is in Soomaa National Park. In spring, when the snow melts, the rivers flood and Soomaa can become flooded for weeks - locals call this the 'fifth season'. During the fifth season, the only way to get around some parts of the park is by dug-out canoe, just as people have done for thousands of years.
Hiking trails wind through Estonian forests and across wooden boardwalks over the bogs. On the boardwalks you can walk right out into the middle of a bog without getting wet, and watch dragonflies, rare orchids, and bog-cotton waving in the breeze. On a clear day, the reflections of clouds in the dark bog pools are breathtaking.
Estonia's forests are also home to mushrooms, blueberries and cranberries that people love to pick in autumn. Foraging - collecting wild food from nature - is a big part of Estonian life, and many families spend weekends walking in the forest with baskets.