MOMENTS IN TIME

• On April 16, 1947, a massive explosion occurs during the loading of fertilizer onto the freighter Grandcamp at a pier in Texas City, Texas, killing 600 people. The blast was heard 150 miles away and was so powerful that the ship's 3,000-pound anchor was found 2 miles away.

• On April 17, 1937, Daffy Duck makes his debut in the Warner Bros. short "Porky's Duck Hunt." In the 1920s, movie houses had started showing a short cartoon before feature presentations, but the form became more popular after sound was introduced in 1928.

• On April 18, 1983, Joan Benoit wins her second Boston Marathon in the women's division with a time of 2:22:43. The inaugural Boston Marathon was run on April 19, 1897, and was a menonly event until 1972, when women were officially allowed to compete.

• On April 19, 1775, at about 5 a.m., 700 British troops march into the Massachusetts town of Lexington to find 77 armed minutemen waiting for them. Suddenly, the "shot heard around the world" was fired from an undetermined gun. When the brief Battle of Lexington ended, eight Americans lay dead or dying and 10 others were wounded. The American Revolution had begun.

• On April 20, 1841, Edgar Allen Poe's short story "The Murders in the Rue Morgue" first appears in Graham's Lady's and Gentleman's Magazine. The tale is generally considered to be the first detective story.

• On April 21, 1918, in the skies over France, Manfred von Richthofen, the notorious German flying ace known as "The Red Baron," is killed by Allied fire. By the time he was 25 years old, Richthofen had downed 80 enemy aircraft.

• On April 22, 1992, dozens of sewer explosions in Guadalajara, Mexico, kill more than 200 people and damage 1,000 buildings. The series of explosions was caused by a gas leak, the warning signs of which were ignored by the Mexican government and the national oil company.