John Aspinwall  ROOSEVELT

 1921 - Charles Strite of Minnesota patents the pop-up toaster.

 1923 to 1927 - Television is invented (Vladimir Kosma Zworykin (Russia), Philo Taylor Farnsworth (United States))

 1927 - The aerosol can is invented (Erik Rotheim, Norway)

 1928 - Sliced bread (bread slicing machine) is invented by Otto Frederick Rohwedder (United States)

1929 - October 29 - Black Tuesday - Stock market crash - The Great Depression Begins - It lasted until 1941 (WW2)

 1930 - Scotch tape is invented (Richard Drew (3M), United States)

 In 1930, on February 18, Pluto was discovered by astronomer Clyde Tombaugh at the Lowell Observatory in Flagstaff, Arizona, marking a significant milestone in the study of our solar system.

 1931 - The paper towel is invented (Arthur Scott, United States)

 1934 - The metal beverage can is invented (American Can Co., United States)

 1935 - The snowmobile was invented by Joseph Bombardier (Quebec, Canada)

 1938 - The ballpoint pen is invented (Lazlo Biro, Hungary)

 1938-1944 - Sunscreen is invented (Franz Greiter, Switzerland and Benjamin Green, United States)

 1938 - October 27 - Du Pont announces a name for its new synthetic yarn: nylon.

 1940 - April - 1st electron microscope demonstrated (RCA), Philadelphia, Pennsylvania, USA

 1945 - The atomic bomb is invented (J. Robert Oppenheimer, et al., United States)

 The microwave oven was invented accidentally in 1945 by Percy Spencer, a Raytheon engineer. While testing a magnetron, he noticed microwaves melted a candy bar in his pocket. Experimenting further, he discovered microwaves could cook food quickly. Raytheon patented the process, and by 1947, they built the first commercial microwave oven, called the 'Radarange.' Initially used in commercial settings, microwaves becomes affordable for home use by the 1960s and 1970s, revolutionizing cooking.

 1948 - Velcro is invented (George de Mestral, Switzerland)

1962 - The Cuban Missile Crisis was a tense 13-day standoff in October 1962 between the United States and the Soviet Union over the installation of Soviet nuclear missiles in Cuba, just 90 miles from the U.S. coast. The crisis is considered the closest the Cold War came to escalating into a full-scale nuclear war. It began when American spy planes discovered the missiles, leading to a U.S. naval blockade of Cuba and intense negotiations. The crisis ended when Soviet Premier Nikita Khrushchev agreed to remove the missiles in exchange for the U.S. promising not to invade Cuba and secretly agreeing to remove American missiles from Turkey.

1963 - I Have a Dream Speech - Martin Luther King's Address at March on Washington August 28, 1963.

 1968 - The ATM is invented (Don Wetzel, United States)

June 17, 1972 – August 9, 1974 - Watergate Scandal began with the break-in at the Democratic National Committee headquarters at the Watergate office complex in Washington, D.C., in 1972. Members of President Richard Nixon's administration attempted to cover up their involvement. The scandal led to the discovery of multiple abuses of power by the Nixon administration, the resignation of President Nixon in 1974, and the indictment of several administration officials.

1973 - January 22 - Roe v. Wade, 410 U.S. 113 and Doe v. Bolton, 410 U.S. 179: The U.S. Supreme Court declares that the Constitution protects women’s right to terminate an early pregnancy, thus making abortion legal in the U.S.

1973 - March 29 - The last United States soldier leaves Vietnam

 The cell phone was invented by Martin Cooper of Motorola. On April 3, 1973, he made the first handheld mobile phone call with the Motorola DynaTAC. This device weighed 2.5 pounds and was 10 inches long, offering 30 minutes of talk time and requiring 10 hours to charge. The first commercial cell phone was released in 1983, revolutionizing communication and leading to the modern smartphones we use today.