Historical timeline for May 15

Prime Minister of Slovakia Robert Fico is shot and critically injured while meeting with supporters at an event in Handlová.

An upsurge in violence in Iraq leaves more than 389 people dead over three days.

Jessica Watson becomes the youngest person to sail, non-stop and unassisted around the world solo.

California becomes the second U.S. state after Massachusetts in 2004 to legalize same-sex marriage after the state's own Supreme Court rules a previous ban unconstitutional.

Arsenal F.C. go an entire league campaign unbeaten in the English Premier League, joining Preston North End F.C. with the right to claim the title "The Invincibles".

A CSX EMD SD40-2 8888 rolls out of a train yard in Walbridge, Ohio, with 47 freight cars, including some tank cars with flammable chemical, after its engineer fails to reboard it after setting a yard switch. It travels south driverless for 66 miles (106 km) until it is brought to a halt near Kenton. The incident became the inspiration for the 2010 film Unstoppable.

The United States government acknowledges the existence of the "Secret War" in Laos and dedicates the Laos Memorial in honor of Hmong and other "Secret War" veterans.

The Space Shuttle Atlantis launches on STS-84 to dock with the Russian space station Mir.

Édith Cresson becomes France's first female Prime Minister.

Soviet–Afghan War: After more than eight years of fighting, the Soviet Army begins to withdraw 115,000 troops from Afghanistan.

Aeroflot Flight 1802 crashes near Viktorivka, Chernihiv Raion, Chernihiv Oblast, killing 52.

Ma'alot massacre: Members of the Democratic Front for the Liberation of Palestine attack and take hostages at an Israeli school; a total of 31 people are killed, including 22 schoolchildren.

The Ryukyu Islands, under U.S. military governance since their conquest in 1945, revert to Japanese control.

President Richard Nixon appoints Anna Mae Hays and Elizabeth P. Hoisington as the first female United States Army generals.

Project Mercury: The launch of the final Mercury mission, Mercury-Atlas 9 with astronaut Gordon Cooper on board. He becomes the first American to spend more than a day in space, and the last American to go into space alone.

At Malden Island in the Pacific Ocean, Britain tests its first hydrogen bomb in Operation Grapple.

Following the expiration of The British Mandate for Palestine, the Kingdom of Egypt, Transjordan, Lebanon, Syria, Iraq and Saudi Arabia invade Israel, thus starting the 1948 Arab–Israeli War.

World War II: The Battle of Poljana, the final skirmish in Europe, is fought near Prevalje, Slovenia.

Joseph Stalin dissolves the Comintern (or Third International).

World War II: In the United States, a bill creating the Women's Army Auxiliary Corps (WAAC) is signed into law.