mostly in boreal ecosystems in the Northern Hemisphere. The world's largest wetland is the peat bogs of the Western Siberian Lowlands in Russia, which cover more than a million square kilometres.[4] Large peat bogs also occur in North America, particularly the Hudson Bay Lowland and the Mackenzie River Basin.[4] They are less common in the Southern Hemisphere, with the largest being the Magellanic moorland, comprising some 44,000 square kilometers. Sphagnum bogs were widespread in northern Europe[5] but have often been cleared and drained for agriculture.