Final answer:
The Frisian Islands in the North Sea, including the island of Sylt, are shared by Germany, Denmark, and the Netherlands. Sylt is the northernmost of Germany's North Frisian Islands, and the region is known for its cultural and ecological significance.
Step-by-step explanation:
The Frisian Islands in the North Sea are shared by Germany, Denmark, and the Netherlands. These islands are a chain that is divided among the countries, with Sylt being the northernmost island of Germany's North Frisian Islands. The Frisian people are a Germanic ethnic group native to the coastal parts of the Netherlands and Germany. This region is known for its unique language and culture, which differ from the mainland's.
These islands are of interest not only for their cultural heritage but also for their natural environment. The Wadden Sea, which lies along the islands, is a UNESCO World Heritage site known for its tidal flats and wetlands that host a rich biodiversity. The isolation of some populations, such as the oysters near Sylt, has led to unique genetic differentiation, highlighting the ecological significance of the region.