Underwater facilities are structures built beneath the surface of oceans, seas, or large bodies of water. These facilities can serve various purposes, including research, tourism, and military operations. They are designed to withstand high pressure and provide a safe environment for scientists, engineers, and visitors to explore marine life and conduct experiments. Examples of underwater facilities include research laboratories, aquariums, and submarine habitats. These structures often feature large windows for viewing the underwater environment and are equipped with advanced technology to support life and work underwater. They play a crucial role in studying ocean ecosystems and developing underwater technologies.