HISTORY FOR TODAY

  Watson and Crick discover chemical structure of DNA On February 28, 1953, Cambridge University scientists James D. Watson and Francis H.C. Crick announce that they have determined the double-helix structure of DNA, the molecule containing human genes. Though DNA—short for deoxyribonucleic acid—was discovered in 1869, its crucial role in determining genetic inheritance wasn’t demonstrated until 1943. In the early 1950s, Watson and Crick were only two of many scientists working on figuring out the structure of DNA. California chemist Linus Pauling suggested an incorrect model at the beginning of 1953, prompting Watson and Crick to try and beat Pauling at his own game.  On the morning of February 28, they determined that the structure of DNA was a double-helix polymer, or a spiral of two DNA strands, each containing a long chain of monomer nucleotides, wound around each other. According to their findings, DNA replicated itself by separating into individual strands, each of which became

  New Orleanians take to the streets for Mardi Gras On February 27, 1827, a group of masked and costumed students dance through the streets of New Orleans, Louisiana, marking the beginning of the city’s famous Mardi Gras celebrations. The celebration of Carnival—or the weeks between Twelfth Night on January 6 and Ash Wednesday, the beginning of the Christian period of Lent—spread from Rome across Europe and later to the Americas. Nowhere in the United States is Carnival celebrated as grandly as in New Orleans, famous for its over-the-top parades and parties for Mardi Gras (or Fat Tuesday), the last day of the Carnival season. Early French settlers brought the tradition of Mardi Gras to the U.S. Gulf Coast at the end of the 17th century. In fact, Mobile, Alabama celebrated its first carnival in 1703. However, Spanish governors later banned the celebrations. After Louisiana Territory became part of the United States in 1803, New Orleanians managed to convince the city council to lift the

  Florida teen Trayvon Martin is shot and killed On February 26, 2012, Trayvon Martin, an African American teen walking home from a trip to a convenience store, is fatally shot by George Zimmerman, a neighborhood watch volunteer patrolling the townhouse community of the Retreat at Twin Lakes in Sanford, Florida. Zimmerman later claimed to have shot the unarmed 17-year-old out of self-defense during a physical altercation.  After police initially opted not to arrest Zimmerman, whose father is white and mother is Hispanic, the case sparked protests and ignited national debates about racial profiling and self-defense laws. Zimmerman later was charged with second-degree murder. Following a high-profile trial that riveted America, he was acquitted of the charges against him. The term “Black lives matter” was then used for the first time by organizer Alicia Garza in a July 13, 2013 Facebook post in response to Zimmerman's acquittal. The phrase spread widely and became a rallying cry agai

  Young Muhammad Ali knocks out Sonny Liston for first world title On February 25, 1964, 22-year-old Cassius Clay shocks the odds-makers by dethroning world heavyweight boxing champ Sonny Liston in a seventh-round technical knockout. The dreaded Liston, who had twice demolished former champ Floyd Patterson in one round, was an 8-to-1 favorite. However, Clay predicted victory, boasting that he would “float like a butterfly, sting like a bee” and knock out Liston in the eighth round.  The fleet-footed and loquacious youngster who would later become known as Muhammed Ali needed less time to make good on his claim—Liston, complaining of an injured shoulder, failed to answer the seventh-round bell. A few moments later, a new heavyweight champion was proclaimed. Cassius Marcellus Clay Jr. was born in Louisville, Kentucky, in 1942. He started boxing when he was 12 and by age 18 had amassed a record of over 100 wins in amateur competition. In 1959, he won the International Golden Gloves heavyw

  Alamo defenders call for help On February 24, 1836, in San Antonio, Texas, Colonel William Travis issues a call for help on behalf of the Texan troops defending the Alamo, an old Spanish mission and fortress under siege by the Mexican army. A native of Alabama, Travis moved to the Mexican state of Texas in 1831. He soon became a leader of the growing movement to overthrow the Mexican government and establish an independent Texan republic. When the Texas revolution began in 1835, Travis became a lieutenant-colonel in the revolutionary army and was given command of troops in the recently captured city of San Antonio de Bexar (now San Antonio). On February 23, 1836, a large Mexican force commanded by General Antonio Lopez de Santa Ana arrived suddenly in San Antonio. Travis and his troops took shelter in the Alamo, where they were soon joined by a volunteer force led by Colonel James Bowie. Though Santa Ana’s 5,000 troops heavily outnumbered the several hundred Texans, Travis and his me