1847 - Naval Forces begin 5 day battle to capture several towns in Mexico.
1861 - Fort Sumter surrenders to Confederate forces.
1960 - Navy's navigation satellite, Transit, placed into orbit from Cape Canaveral, FL and demonstrates ability to launch another satellite.
2009 - In a daring high-seas rescue, U.S. Navy SEAL snipers killed three Somali pirates and freed the American sea captain who had offered himself as a hostage to save his crew.
1898 - Commissioning of first Post Civil War hospital ship, USS Solace.
1969 - North Korean aircraft shoots down Navy EC-121 reconnaissance aircraft from VQ-1 over the Sea of Japan.
1988 - USS Samuel B. Roberts struck Iranian mine off Qatar.
1989 - First Navy ship arrives on scene to assist in Exxon Valdez oil spill cleanup.
1885 - Naval forces land at Panama to protect American interests during revolution.
1912 - USS Chester and USS Salem sailed from MA to assist RMS Titanic survivors.
1918 - First Marine Aviation Force formed at Marine Flying Field, Miami, FL.
1961 - Launching of first nuclear-powered frigate, USS Bainbridge, at Quincy, MA.
1962 - USS Princeton brought first Marine helicopters to Vietnam. This was first Marine advisory unit to arrive in South Vietnam.
1986 - Operation Eldorado Canyon, Navy aircraft from USS America (CV-66) and USS Coral Sea (CV-43) attack Libya in conjunction with USAF aircraft after Libya linked to terrorist bombing of West Berlin discotheque which killed 1 American and injured 78 people.
1863 - Union gunboats pass Confederate batteries at Vicksburg.
1924 - Navy commences relief operations in Mississippi Valley floods, lasting until 16 June.
1947 - Act of Congress gives Navy Nurse Corps members commissioned rank.
1959 - Helicopters from USS Edisto begin rescue operations in Montevideo, Uruguay. By 26 April they had carried 277 flood victims to safety.
1778 - Sloop-in-war Ranger captures British brig.
1848 - U.S. Navy expedition to explore the Dead Sea and the River Jordan, commanded by LT William F. Lynch, reaches the Dead Sea.
1906 - Navy assists in relief operations during San Francisco earthquake and fire.
1942 - USS Hornet launches Doolittle's Army bombers for first attack on Japan.
1988 - Navy destroys 2 Iranian surveillance platforms, sinks one frigate and one patrol ships, and severely damages a second frigate in retaliation for attack on USS Samuel B. Roberts.
1783 - George Washington proclaims end of hostilities.
1861 - President Lincoln orders blockade of Southern ports from SC to Texas.
1955 - USS Albany and USS William Wood begin to provide disaster relief to citizens of Volos, Greece, ending 21 April.