Underwater caves are natural formations found beneath the surface of water, often created by the erosion of rock over thousands of years. These caves can be filled with freshwater or saltwater and are typically formed in limestone, which is susceptible to dissolution. They can vary in size and complexity, ranging from small tunnels to extensive systems that stretch for miles. Exploring underwater caves requires specialized training and equipment, as they can be challenging and dangerous environments. Divers must be aware of potential hazards such as strong currents, low visibility, and the risk of getting lost. Many underwater caves are also home to unique ecosystems, housing various species of fish and other aquatic life.