A manned submersible is a type of underwater vehicle designed to carry humans into deep ocean environments. These vessels are equipped with strong materials to withstand high pressure and often feature large viewports for observation. Manned submersibles are used for scientific research, exploration, and underwater tourism. These vehicles can reach significant depths, allowing scientists to study marine life and geological formations. Notable examples include the Bathyscaphe Trieste, which reached the Challenger Deep, and the Alvin, used for deep-sea research. Manned submersibles play a crucial role in expanding our understanding of the ocean's mysteries.