The document discusses the history and development of submarines from the early 17th century up to World War 1. It describes some of the first submarines like one built in 1620 by Cornelius van Drebbel and how submarines have changed significantly since then. During World War 1, technical developments greatly improved submarines that were used as weapons by Germany. Examples mentioned include the Deutschland class U-boats that could carry cargo and the U-155 combat submarine. Submarines were also used by other countries in World War 1 like the USS O-7 from the United States and the HMAS AE2 from Australia.