January 1900: U.S. announces Open Doors Policy to promote their trade with China.
February 1900: British Labour Party is created.
March 1900: The U.S. enacts the Gold Standards Act.
April 1900: Paris Exposition. Belgian anarchist Jean-Baptiste Sipido tried to shot the future Edward VII but ends up wounding someone else instead. [This is the first point of divergence]
May 1900: The second Modern Olympic Games opens in Paris (as part of the Paris World Exhibition).
June 1900: Boxer Rebellion: Boxers gather about 20,000 people near Peking, and kill hundreds of European citizens, including the German ambassador.
July 1900: The first zeppelin flight is carried out over Lake Constance, near Friedrichshafen, Germany.
August 1900: Boxer Rebellion: An international contingent of troops, under British command, invades Peking and frees the European hostages.
September 1900: The 1900 Galveston hurricane kills about 6,000–12,000 people.
October 1900: Max Planck discovers the law of black-body radiation (Planck's law).
November 1900: U.S. presidential election, 1900: William McKinley is re-elected president, defeating William Jennings Bryan in a rematch.
December 1900: Max Planck announces his discovery of the law of black body emission, marking the birth of quantum physics.
January 1901: Nigeria becomes a British protectorate.
February 1901: The funeral of Queen Victoria is held at St George's Chapel, Windsor Castle.
March 1901: A showing of 71 Vincent van Gogh paintings in Paris, 11 years after his death, creates a sensation.
April 1901: New York becomes the first U.S. state to require automobile license plates.
May 1901: In New Jersey, the Edison Storage Battery Company is founded.
June 1901: Cuba becomes a United States protectorate.
July 1901: The first United Kingdom Fingerprint Bureau is established at Scotland Yard, the Metropolitan Police headquarters in London, by Edward Henry.
August 1901: Peter O'Connor sets the first International Association of Athletics Federations recognised long jump world record, of 24 ft 11¾ins. The record will stand for 20 years.
September 1901: U.S. Vice President Theodore Roosevelt utters the famous phrase, "Speak softly and carry a big stick", at the Minnesota State Fair.
October 1901: The British Royal Navy's first submarine, Holland 1, is launched at Barrow-in-Furness.
November 1901: Sigma Phi Epsilon is founded in Richmond, Virginia.
December 1901: The first Nobel Prize ceremony is held in Stockholm, on the fifth anniversary of Alfred Nobel's death.
January 1902: The first college football bowl game, the Rose Bowl between Michigan and Stanford, is held in Pasadena, California.
February 1902: The Berlin U-Bahn underground is opened.
March 1902: Real Madrid C.F. is founded as Madrid Football Club.
April 1902: Electric Theatre, the first movie theater in the United States, opens in Los Angeles.
May 1902: Cuba gains independence from the United States.
June 1902: The New York Central Railroad inaugurates the 20th Century Limited passenger train between Chicago and New York City.
July 1902: Erik Gustaf Boström returns as Prime Minister of Sweden.
August 1902: 100 miners die in a pit explosion in Wollongong, Australia.
September 1902: The first science fiction film, the silent A Trip to the Moon (Le Voyage dans La Lune), is premièred at the Théâtre Robert-Houdin in Paris, France, by actor/producer Georges Méliès, and proves an immediate success.
October 1902: The first Borstal (youth offenders' institution) opens in Borstal, Kent, U.K.
November 1902: The first teddy bear is produced by Morris Michtom in the United States.
December 1902: The first Aswan Dam on the Nile is completed.
January 1903 till March 1912: [Although it might proceed different from OTL it's ultimately too mundane to be meaningfully noted here.]
April 1912: RMS Titanic sank as usual, but nearby ships arrived in time to save more passengers than OTL.
May 1912 till 1943: Mundane as usual.
** The mother thread is unexpectedly relegated to necroland and I've hard time completing the TL alone per your rules so giving up at this point. At lease I'm bringing it to a more honorable ending. **
1944: Nazi rocket scientist Klaus Riedel survived the car accident that would've killed him in OTL.
1945: Anthony Marchione was shot down by part of the Imperial Japanese air force, causing General Mcarthur to interpret this as an act of non-surrender. Small skirmishes between US and Japanese forces ensued but it was quickly brought to a resolution fortunately. At the same time rocket scientists Rudolf Nebel and Klaus Riedel are recruited by the US.
1953: USA launched the world's first ICBM based on the RTV Hiroc design, however that program was prematurely terminated and superseded afterwards after iving on a string of tight budgets.
October 4, 1957: USSR launched Sputnik 1 into space, which is the first artificial satellite.
November 3, 1957: Sputnik 2 is launched, carrying Laika the first dog in orbit.
December 6, 1957: The US launched its first satellite into space, Vanguard I.
January 31, 1958: USA sent up another satellite Explorer I into space.
March 5, 1958: NASA's Explorer II is launched into orbit.
April 27, 1958: Sputnik 3 launched by USSR.
January 2, 1959: SU takes one step further by sending Luna 1 into the cislunar space and beyond.
January 20, 1961: Inauguration of President Kennedy.
January 31, 1961: NASA sent up Ham the Chimp into space.
April 12, 1961: Cosmonaut Yuri Gagarin became the first man in space and in orbit, however his mission is a partial failure since Vostok's retrorockets failed before intended reentry causing him to enter the code to unlock the controls and attempt to control his spacecraft to no avail. Fortunately he safely landed inside the United States due to natural orbital decay in lower orbits few days later.
May 5, 1961: NASA's Alan Shepard is the first American in space with a 15 minute suborbital flight, and with a recoverable booster.
May 25, 1961: US President Kennedy delivers his speech to put a man on the Moon in the Congress. Afterwards Khrushchev orders Korolev to do the same thing.
July 21, 1961: Mercury Redstone 4 carrying Gus Grissom commences with the usage of the booster recovered from Shepard's flight.
February 20, 1962: John Glenn became the first American to orbit the Earth.
July 22, 1962: Mariner 1 is launched, and would become the first probe to fly by a planet (Venus) later.
November 1, 1962: Yevgeni Andreyev and Pyotr Dolgov survived their space dive. Soviet probe Mars 1 is successfully sent to the direction of Mars.
June 16, 1963: Valentina Tereshkova is the first woman in space.
June 19, 1963: Mars 1 closest approach at 193,000 km from Mars. It also sent back first close-up images of the red planet.
March 18, 1965: Alexei Leonov is the first person to do a extravehicular spacewalk.
November 2, 1965: Voskhod 3 lifts off into space and flew into the vicinity of the Van Allen Belt.
February 3, 1966: Luna 9 is the first object to soft land on the moon.
March 15, 1966: Irina Solovyova is the first woman to spacewalk in the Voskhod 4 mission.
January 27, 1967: Apollo 1 disaster.
April 26, 1967: Soyuz 1 performed a hard landing onto the ground. Vladimir Komarov survived but is permanently left disabled.
December 24, 1968: Apollo 8 became the first manned mission to orbit the Moon.
Early 1969: USA's Surveyor rover is sent to the Moon where it successfully lands, stunning the world.
May 17, 1969: Yuri Gagarin and Viktor Gorbatko became the first Soviet cosmonauts to orbit the Moon in a Soyuz 7K-LOK spacecraft.
July 20, 1969: Apollo 11 landed on the Moon which is the first manned mission to do so.
November 4, 1969: USSR followed suit by sending Alexei Leonov to land on the Moon.
March 1970: In tandem with the lunar mission, NASA launched the world's first space station "Olympus" based on
LM lab design. There would be two missions to dock on it and conduct experiments.
December 15, 1970: Venera 7 soft lands on Venus.
April 12, 1971: Launch of Salyut 1 the second space station.
April 22, 1971: Soyuz 10 launched which will become the first manned mission to enter the Salyut 1 station.
June 12, 1971: Soviet Russia's Irina Solovyova is the first woman to walk on the Moon.
March 2, 1972: Pioneer 10 is launched to Jupiter.
April 6, 1973: Pioneer 11 is launched to Jupiter and Saturn.
October 6 - 25, 1973: Yom Kippur War.
Circa 1974: Mariner 10 is the first to reach Mercury while Pioneer H is launched as an out-of-the ecliptic mission.
July 15, 1975: Apollo Soyuz test project is launched into space.
Early July 1976: The final Apollo 22 mission is the first working base on another celestial body with the deployment of a
lunar shelter, dealing a final blow to the Soviets in the race for space supremacy.
July 20, 1976: NASA's Viking 1 lands on Mars and successfully performed its mission. At the same year they sent up monkey into space for a year in name of biological testing.
September 5, 1977: NASA launched Voyager 1 to the outer planets and beyond.
April 12, 1981: Space Shuttle Columbia makes its maiden flight.
March 9, 1989: Start of a series of revolutions in the Eastern Bloc.
November 9, 1989: Fall of the Berlin Wall.
December 26, 1991: End of the Cold War as the USSR vanish from existence.
November 16, 1996: Russia's Mars 96 is launched to Mars.
1999: Columbine tragedy ends up much worse than OTL when the shooters' gas bombs succeeded in exploding which kills much more people.