De Oostvaardersplassen is a nature reserve located in the Netherlands, established in 1986. It spans approximately 56 square kilometers and is known for its unique wetland ecosystem, which includes marshes, grasslands, and forests. The area is home to a variety of wildlife, including wild horses, red deer, and European bison, which were introduced to the reserve to maintain the natural landscape. The reserve is part of the larger Flevoland province and serves as an important habitat for many bird species, making it a popular destination for birdwatchers. It is also recognized for its role in conservation and ecological research, attracting visitors interested in nature and wildlife.