Sylt (; ; Söl'ring North Frisian: ) is a former island in northern Germany, part of Nordfriesland district, Schleswig-Holstein, and well known for the distinctive shape of its shoreline. It belongs to the North Frisian Islands and is the largest island in North Frisia. The northernmost island of Germany, it is known for its tourist resorts, notably Westerland, Kampen and Wenningstedt-Braderup, as well as for its sandy beach. It is frequently covered by the media in connection with its exposed situation in the North Sea and its ongoing loss of land during storm tides. Since 1927, Sylt has been connected to the mainland by the Hindenburgdamm causeway. In later years, it has been a resort for the German jet set and tourists in search of occasional celebrity sightings.
Geography
With , Sylt is the fourth-largest German island and the largest German island in the North Sea. Sylt is located from off the mainland, to which it is connected by the Hindenburgdamm. Southeast of Sylt are the islands of Föhr and Amrum, to the north lies the Danish island of Rømø. The island of Sylt extends for in a north-south direction. At its northern point at Königshafen, it is only wide. Its greatest width, from the town of Westerland in the west to the eastern Nössespitze near Morsum, measures . On the western and northwestern shore, there is a sandy beach. To the east of Sylt, is the Wadden Sea, which belongs to the Schleswig-Holstein Wadden Sea National Park and mostly falls dry during low tide.
The island's shape has constantly shifted over time, a process which is still ongoing today. The northern and southern spits of Sylt are exclusively made up of infertile sand deposits, while the central part with the municipalities of Westerland, Wenningstedt-Braderup and Sylt-Ost consists of a geestland core, which becomes apparent in the form of the Red Cliff of Wenningstedt. The geestland facing the Wadden Sea gradually turns into fertile marshland around Sylt-Ost. Sylt has only been an island since the Grote Mandrenke flood of 1362. The so-called Uwe-Düne (Uwe Dune) is the island's highest elevation with above sea level.
The island in its current form has only existed for about 400 years. Like the mainland geestland, it was formed of moraines from the older ice ages, thus being made up of a till core, which is now apparent in the island's west and centre by the cliff, dunes and beach. This sandy core began to erode as it was exposed to a strong current along the island's steep basement when the sea level rose 8000 years ago. During the process, sediments were accumulated north and south of the island. The west coast, which was originally situated off today's shore, was thus gradually moved eastward, while at the same time the island began to extend to the north and south. After the ice ages, marshland began to form around this geestland core.
In 1141, Sylt is recorded as an island, yet before the Grote Mandrenke flood it belonged to a landscape cut by tidal creeks and, at least during low tide, it could be reached on foot. It is only since this flood that the creation of a spit from sediments began to form the current characteristic shape of Sylt. It is the northern and southern edges of Sylt which were, and still are, the subject of greatest change. For example, Listland was separated from the rest of the island in the 14th century and from the later 17th century onwards the Königshafen (King's Harbour) began to silt up as the "elbow" spit began to form.
In addition to the constant loss of land, the inhabitants during the Little Ice Age were constrained by sand drift. Dunes shifting to the east threatened settlements and arable land and had to be stopped by the planting of marram grass in the 18th century. Consequently, though, material breaking off the island was increasingly washed away and the island's extent continued to decrease.
Records of the annual land loss exist since 1870. According to them, Sylt lost an annual of land in the north and in the south from 1870 to 1951. From 1951 to 1984, the rate increased to and respectively, while shorelines at the island's very edges at Hörnum and List are even more affected.
Severe storm surges of the last decades have repeatedly endangered Sylt to the point of breaking in two, e.g. Hörnum was temporarily cut off from the island in 1962. Part of the island near Rantum which is only 500 m wide is especially threatened.