1513 Spanish explorer Vasco Núñez de Balboa reaches what would become known as the Pacific Ocean.
1520 The Strait of Magellan, the passage immediately south of mainland South America, connecting the Pacific and the Atlantic Oceans, is first navigated by Ferdinand Magellan during his global circumnavigation voyage.
1520 After navigating through the South American strait, three ships under the command of Portuguese explorer Ferdinand Magellan reach the Pacific Ocean, becoming the first Europeans to sail from the Atlantic Ocean to the Pacific.
1610 Henry Hudson sails into what it is now known as Hudson Bay thinking he had made it through the Northwest Passage and reached the Pacific Ocean.
1793 Alexander Mackenzie reaches the Pacific Ocean becoming the first Euro-American to complete a transcontinental crossing of Canada.
1806 After traveling through the Louisiana Purchase and reaching the Pacific Ocean, explorers Lewis and Clark and their "Corps of Discovery" begin their arduous journey home.
1855 The first locomotive runs from the Atlantic Ocean to the Pacific Ocean on the Panama Railway.
1899 The United States takes possession of Wake Island in the Pacific Ocean.
1902 The Commercial Pacific Cable Company lays the first Pacific telegraph cable, from Ocean Beach, San Francisco to Honolulu, Hawaii.
1914 World War I: the first British Royal Navy defeat of the war with Germany, the Battle of Coronel, is fought off of the western coast of Chile, in the Pacific, with the loss of HMS Good Hope and HMS Monmouth.
1928 Charles Kingsford Smith completes the first trans-Pacific flight in a Fokker Trimotor monoplane, the ''Southern Cross''.
1937 Amelia Earhart and navigator Fred Noonan are last heard from over the Pacific Ocean while attempting to make the first equatorial round-the-world flight.
1942 World War II: The two-person crew of the U.S. naval blimp L-8 disappears without a trace on a routine anti-submarine patrol over the Pacific Ocean. The blimp drifts without her crew and crash-lands in Daly City, California.
1942 U.S. Marines raid the Japanese-held Pacific island of Makin (Butaritari).
1944 World War II: Operation Hailstone begins. U.S. naval air, surface, and submarine attack against Truk (Chuuk), Japan's main base in the central Pacific, in support of the Eniwetok invasion.
1947 Thor Heyerdahl's balsa wood raft the Kon-Tiki, smashes into the reef at Raroia in the Tuamotu Islands after a 101-day, {{Convert|7000|km|mi}} journey across the Pacific Ocean in an attempt to prove that pre-historic peoples could have traveled from South America.
1954 Nuclear testing: The Castle Bravo, a 15-megaton hydrogen bomb, is detonated on Bikini Atoll in the Pacific Ocean, resulting in the worst radioactive contamination ever caused by the United States.
1956 In Operation Redwing (shot ''Cherokee''), the first United States airborne hydrogen bomb is dropped over Bikini Atoll in the Pacific Ocean;
1960 The bathyscaphe USS ''Trieste'' breaks a depth record by descending to 10,911 m (35,798 feet) in the Pacific Ocean.
1962 A Flying Tiger Line Super Constellation disappears in the western Pacific Ocean, with 107 missing.
1963 A Northwest Airlines DC-7 crashes in the Pacific Ocean off the coast of British Columbia, killing 101.
1968 Apollo Program: Apollo 8 splashes down in the Pacific Ocean, ending the first orbital manned mission to the Moon.
1969 Apollo program: ''Apollo 11'' splashes down safely in the Pacific Ocean.
1969 Apollo program: The Apollo 12 command module splashes down safely in the Pacific Ocean, ending the second manned mission to the Moon.
1979 Varig 707-323C freighter, flown by the same commander as Flight 820, disappears over the Pacific Ocean 30 minutes after taking off from Tokyo.
1995 Steve Fossett lands in Leader, Saskatchewan, Canada becoming the first person to make a solo flight across the Pacific Ocean in a balloon.
1996 Aeroperú Flight 603, a Boeing 757, crashes into the Pacific Ocean shortly after takeoff from Lima, Peru, killing 70.
2000 Alaska Airlines flight 261 MD-83, experiencing horizontal stabilizer problems, crashes in the Pacific Ocean off the coast of Point Mugu, California, killing all 88 persons aboard.
2001 The Russian ''Mir'' space station is disposed of, breaking up in the atmosphere before falling into the southern Pacific Ocean near Fiji.