Liverpool have produced one of the greatest comebacks in Champions League history to beat Barcelona 4-0, overturning a three-goal first-leg deficit and advancing to the final with a 4-3 aggregate victory.
Liverpool will play the winner of Thursday's (NZT) other semi-final between Ajax and Tottenham, with the Dutch side leading 1-0 from the first-leg in London.
Without injured strikers Mohamed Salah and Roberto Firmino, Liverpool took a seventh-minute lead, when a poor headed clearance from Jordi Alba fell at the feet of Jordan Henderson, who burst goalwards.
His low shot was parried out by Barca keeper Marc-Andre ter Stegen, but straight to Divock Origi, who slotted home.
The game took a remarkable turn, after the introduction of Liverpool midfielder Georginio Wijnaldum at the break. The Dutchman drove home a low cross from Trent Alexander-Arnold, which Barca keeper Ter Stegen should have saved, to make it 2-0.
Minutes later, Wijnaldum rose to meet a Xherdan Shaqiri cross with a powerful header to make it 3-3 on aggregate.
Liverpool then grabbed an extraordinary fourth goal, with a quickly-taken corner from Alexander-Arnold, catching the Barca defence asleep with a low ball that was turned in at the near post by Origi.
"It was overwhelming," said manager Jurgen Klopp, amid wild celebrations at the final whistle, when his team stood in front of their famous Kop stand to sing 'You'll Never Walk Alone' with fans.
"I would say it's impossible. Playing against the best team in the world, winning with a clean sheet - I don't know how the boys did it, it's unbelievable.
"I saw James Milner crying after the game on the pitch. It means so much to all of us.
"There are more important things in the world, but creating this emotional atmosphere together is so special."
Liverpool became only the third team in the history of the European Cup or Champions League to come from three goals down after the first leg of a semi-final and progress, after Panathinaikos in 1970-71 and Barcelona themselves in 1985-86.
It was a night that will be remembered by Liverpool fans, alongside their fifth European Cup win in Istanbul in 2005, when they came back from 3-0 down at half-time to win on penalties.
Klopp was almost lost for words, as he tried to express his feelings.
"The whole game, the whole performance was too much," he said. "It was overwhelming.
"I watched in my life so many football games, but I can't remember many like this."
The scoreline was remarkable enough in itself, but the fact that Liverpool overcame five-times European champions Barcelona, without Mo Salah and Roberto Firmino, made it extraordinary.
Klopp also swore during his post-match interview and said he might be fined because of it.
"It's 10 past 10, most of your children are probably in bed, but these boys are f*****g talented giants. It's unbelievable.
"Fine me, if you want. I'm not native, so I don't have better words for it."