Born in 1940 as Nazi bombs battered Liverpool from above, young Lennon's life was pockmarked by familial battles. He was given up by his mother, Julia, to his Aunt Mimi, a formal yet loving caretaker with whom he remained close the rest of his life. This came after his father, Alf, tried to take him to New Zealand in secret, and Lennon, at five, had to choose between his parents. It would scar him forever. He remained close with Julia, who acted like an aunt and taught him to play the banjo, until her death in 1957, which would haunt him for the rest of his life, as well. His song "Mother" was the result of primal therapy in 1970 meant to finally deal with the abandonment and death.
1960: The Quarrymen Become The Beatles
With the addition of George Harrison -- who Lennon at first believed to be too young, as he was just 14-years old -- and Stu Sutcliffe, the Quarrymen, originally a skiffle band, became The Beatles. They played around with a series of names, but ended up making a pretty decent choice.
1962: The Beatles Release "Love Me Do"
And so Beatlemania began, as the group released their first single, "Love Me Do." It's other side contained the track "P.S. I Love You." It hit #17 in Britain, and two years later, #1 in America.
February 15, 1964: Appearing on "The Ed Sullivan Show"
This was the moment that kicked off Beatlemania in the USA: playing "I Want to Hold Your Hand" on The Ed Sullivan Show, above the raucous hysteria of screaming girls getting their first glimpse at the Lads from Liverpool.
The Beatles' first film and one of their biggest hits, the song was upbeat, but represented a cry for actual help. It came during what Lennon called his "Fat Elvis" period.
1965: Lennon Writes "Help!" and Gets a Royal Honor From the Queen
Thought it was a cheery song and the title of a film, Lennon really was reaching out for some help with this track; the weight of the band was beginning to get to him. The band received the honor of Members of the Order of the British Empire (MBE) from the Queen; Lennon would eventually give his award back.
1966: Lennon Meets Yoko Ono
While still married to teenage love Cynthia, the mother of his son Julian, Lennon met avant garde artist Ono at one of her exhibits in London. They connected on one of her conceptual pieces, and he stayed intrigued by her until they connected again. Many people say that Ono was partially responsible for the band's breakup, in that the rest of the group did not like her collaboration or influence on John. They had a formal wedding and had a son named Sean in 1975.
1967: The release of "Sgt. Pepper's Lonely Hearts Club Band"
A revolutionary album -- and considered by many the finest rock album of all time -- this concept piece (one of the first, along with The Who Sell Out), introduced psychadelia in a big way to the band's work.
1961: John and Yoko Stage Bed-Ins for Peace
One of Lennon's most famous acts of civil disobedience came from just simply not getting out of bed. Twice he and wife Yoko Ono stayed in bed and invited the press to cover their antics, appealing for world peace and reading letters from fans and supporters. The first one took place in Amsterdam, and the second in Montreal.
1970: Moving Past The Beatles
Once The Beatles broke up, Lennon quickly moved on to his own solo career. He released "John Lennon/Plastic Ono Band," his first solo album, and became a peace activist full time, leading protests and nearly getting himself kicked out of the United States a few years later.
1971: "Imagine" is Released
For all his famous Beatles songs, including "Strawberry Fields Forever," it is "Imagine" that is perhaps most closely identified with Lennon's legacy. An appeal for peace, from war and religion and racism, it is a simple song with a powerful message. The word graces his memorial in Central Park, as well.
1971: War is Over, If You Want It
After his bed-ins in 1969, Lennon became a principal leader in the anti-war movement. In 1971, he and Yoko released the single "Happy XMas (War is Over)" and paid for billboards and posters with the phrase "War is Over" to be distributed.
1975: Sean Lennon is Born
Lennon had another son, Julian, born while he was with The Beatles, but did not provide the kind of fatherly love one might expect, so torn between his band's whirlwind existence and still smarting from the abandonment of his own father. In 1975, Sean was born, and he stayed home to raise him in a way he did not Julian. Today, Sean is a musician in his own right.
1980: The release of "Double Fantasy"
What would be Lennon's last album, Double Fantasy marked a musical comeback after a five year hiatus from the business to raise his son, Sean. The album, a collaboration with Yoko, won the Grammy Award for Best Album.
December 9, 1980: Lennon is Assassinated by Mark David Chapman
Shot just outside his residence at The Dakota in Manhattan's Upper West Side, Lennon was killed by Mark David Chapman, who had camped outside the apartment building. He has said that he had considered killing other celebrities before Lennon, but found Lennon the most accessible. The 40-year old legend had just returned from working at his studio.
December 14, 1980: The Rally for John
Just five days after his death, 50,000 people gathered in a silent vigil for John in Central Park, across the street from his residence at The Dakota. Every year, on his birthday and the anniversary of his death, fans gather to pay tribute.
UPDATED: The film mogul addresses a range of issues during his keynote speech at the UCLA Entertainment symposium, including calling on California governor Jerry Brown to back stronger production tax incentives. Read More