April 28 (UPI) -- On this date in history:
In 1788, Maryland ratified the U.S. Constitution, becoming the seventh state of the Union.
In 1789, the most famous of all naval mutinies took place aboard the HMS Bounty en route from Tahiti to Jamaica.
In 1930, the first night game in organized baseball history was played in Independence, Kan.
In 1947, Thor Heyerdahl and five crew members began a trip from Peru to Polynesia on the Kon-Tiki, a raft raft made of balsa logs and other natural materials. The voyage covered 4,300 miles over 101 days.
In 1955, the Public Health Service urged parents to move swiftly in having their children vaccinated for polio.
In 1975, North Vietnamese forces advanced to the outskirts of Saigon in the Vietnam War. Two days later, South Vietnam surrendered.
In 1988, an Aloha Airlines Boeing 737 lost an 18-foot section of its roof at 24,000 feet between Hilo, Hawaii, and Honolulu, killing a flight attendant. The pilot landed on Maui with the remaining 94 passengers and crew members, 61 of them injured.
In 1995, an underground gas explosion at a subway construction site killed about 100 people in Taegu, South Korea.
In 1996, a rampage by a gunman in Port Arthur, Tasmania, Australia, killed 35 people.
In 2005, a Shiite-led Cabinet was approved by Iraq's National Assembly for its first freely elected government.
In 2009, U.S. Sen. Arlen Specter of Pennsylvania, winding up his fifth term as a Republican stalwart, announced he would seek re-election in 2010 as a Democrat, switching parties because he found himself "increasingly at odds" with the Republican Party.
In 2013, renowned concert cellist Janos Starker, who gave his first public performance at age 6 as a child prodigy in Hungary, died in Bloomington, Ind. He was 88.