What is a bog? A bog is a wetland in Estonia that used to be a lake. Wetlands cover around 22% of Estonian surface, with 6% belonging to bogs. Over thousands of years, the lake started overgrowing with plants. The plants didn’t have enough time or possibility to fully decompose, so they basically piled up into a graveyard of plants. When the plants are piled-up, it formes into partially decayed plant material called peat. It's a mix of water and land. When you step on it, it feels spongy and squishy.
Bogs are important in Estonian folklore and culture, they are seen as places of mystery and peace.
Probably the most fun thing to do in a bog is to throw on your bog shoes and walk on the spongy, wet landscape.