The exact number of people who gathered on Central Park to see Elton John on September 13th, 1980 will never be known. The figures 300,000 and 400,000 have both been reported, but a 2008 New York Times article revealed that the numbers were basically bullshit. "You would get in a room with the producer, with a police official, and a person from parks, and someone would say, 'What does it look like to you?'" said Doug Blonsky, a former city parks administrator. "The producer would say, 'I need it to be higher than the last one.' That's the kind of science that went into it."
There may not have been 400,000 people there that day, but video of the event shows a crowd that looks every bit as massive as what Simon and Garfunkel drew the following summer. They saw a stellar show that included big hits like "Your Song," "Bennie and the Jets" and "Tiny Dancer" mixed with new tunes like "Little Jeannie" and "Sartorial Eloquence" and deep cuts like "Have Mercy on the Criminal" and "Harmony." This also got to see Elton reunite with bassist Dee Murray and drummer Nilgel Olsson from the original Elton John Band.
Near the end he played a cover of John Lennon's "Imagine." "We're going to do a song written by a friend of mine who I haven't seen for a long time," said John. "It's a very beautiful song. You all know it. He only lives just over the road. He hasn't done a record in ages, but he's doing one at the moment."
John and Lennon became very close in the mid-1970s. Elton even coaxed him onstage for a couple of songs at Madison Square Garden in 1974, which wound up being his final public performance. As Elton indicated, they didn't see each other very often after Lennon largely walked away from public life in 1976. The new album he referenced was Double Fantasy. Nobody would hear any of it until lead single "(Just Like) Staring Over" hit a month later, but anticipation was very high. It's quite possible home Elton was home in his Dakota right off Central Park during the concert.
Elton played "Imagine" throughout his 1980 tour, but it took on added significance after December 8th when Lennon was murdered by a deranged fan right outside of the Dakota. John hasn't done the song since that horrible month. It probably just became too painful, though in 1981 he did record "Empty Garden" as a tribute to his late friend.