People kayak in a flooded meadows in the Soomaa National Park, Estonia March 17, 2019. Tourists in Soomaa National Park in southern Estonia took to canoes and kayaks for their visit on Sunday (March 17) as meadows and woods in the park flooded in an annual event known locally as a 'fifth season'. REUTERS/Ints Kalnins

People kayak in a flooded meadows in the Soomaa National Park, Estonia March 17, 2019. Aivar Ruukel, who organises tours of the park, said a 'fifth season' occurred when melting snow or spring rains cause flooding of up to 100 square kilometres (38 sq miles) in the park. REUTERS/Ints Kalnins

People kayak in a flooded meadows in the Soomaa National Park, Estonia March 17, 2019. The name 'fifth season' is used by people in the villages in the region, Ruukel said, and is so called because the flooding event is annual and can overlap with the more well-known other four seasons. REUTERS/Ints Kalnins

People kayak in a flooded meadows in the Soomaa National Park, Estonia March 17, 2019. Tourists said they enjoyed the feeling of being in boats among the trees, despite frozen patches and particularly shallow spots making it difficult to get around. REUTERS/Ints Kalnins

People kayak in a flooded meadows in the Soomaa National Park, Estonia March 17, 2019. REUTERS/Ints Kalnins

People kayak in a flooded meadows in the Soomaa National Park, Estonia March 17, 2019. REUTERS/Ints Kalnins