Sites of Special Scientific Interest (SSSIs) are designated areas in the United Kingdom that are recognized for their unique natural features and biodiversity. These sites are protected to conserve their ecological and geological significance, ensuring that important habitats and species are preserved for future generations. SSSIs can include a variety of environments, such as wetlands, woodlands, and coastal areas. They are monitored and managed by organizations like Natural England and Natural Resources Wales, which work to maintain the health of these sites and promote sustainable practices to protect their valuable ecosystems.