A one of a kind unique nature reserve, the huge Wadden Sea, which spans three countries (Denmark, Germany and Netherlands), is one of the worlds top ten tidal flats, and was granted UNESCO World Heritage Site status in 2009. Four times daily, a billion cubic meters of water is moved through the Wadden Sea, and the tide creates mudflats and sandflats by moving mud and sand in dramatic fashion. While the tides make a huge impression twice daily, the area is also unique for the number of migrating birds in spring and autumn – a total of 10-12 million.  The sea is also breeding area for important fish species as well as seals.