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The document discusses the history of ocean exploration from 1900 to present day. Some key developments include the U.S. Navy accepting the first submarine built by John Holland in 1900, the invention of scuba gear by a French man in 1926, and the launch of the first nuclear submarine by the U.S. in 1955. Scuba diving is now mainly used for tourism rather than research, while submarines are primarily employed for military purposes.Read less