Valencia are the dominant force this week, with the competition's top scorer leading the line.
Arsenal, Chelsea, Frankfurt and Valencia have made it to the last four; find out all about them.
Eintracht scraped through on away goals against Benfica, to join Arsenal, Chelsea and Valencia in the last four.
Barcelona are in their 16th semi while Tottenham end a 57-year absence: all four teams' record at this stage.
Fernando Llorente's strike proved decisive as Spurs edged a pulsating tie on away goals.
Barcelona take on Liverpool and Tottenham meet Ajax for a place in the final. Have they met before?
Lionel Messi is out on his own at the top of this season's UEFA Champions League goalscoring charts.
Liverpool completed a 6-1 aggregate win to book a semi-final against Barcelona.
All you need to know about the 2018/19 UEFA Champions League semi-finalists.
Cristiano Ronaldo and Lionel Messi have both pulled further clear at the top of the all-time rankings.
Liverpool won 5-0 at Porto last season but Jürgen Klopp warns that his side face a stiffer challenge this time.
Mauricio Pochettino tells his Tottenham team to keep the faith as they take a narrow lead to City.
Europe's top scorer: is it Olivier Giroud, Munas Dabbur, Lionel Messi or Nõmme Kalju's Liliu?
Lionel Messi's first-half double led Barcelona past Manchester United and into the last four.
Donny van de Beek and Matthijs de Ligt scored the goals as Ajax came from behind to down Juventus in Turin.
Juventus have the benefit of an away goal, but know better than to take Real Madrid's vanquishers lightly.
Barcelona defend a 1-0 lead at the scene of one of United's greatest triumphs.
"Sometimes Barcelona leave you space to play in," says Romelu Lukaku, still optimistic about Manchester United's chances.
Napoli must overturn a 2-0 first-leg loss at Arsenal, banking on their fine European home form to salvage the tie.
A late first-leg goal from Marcos Alonso earned Chelsea a win at Slavia Praha, who must now end the Blues' unbeaten run.
Two late goals have put Valencia in control of the all-Spanish quarter-final, giving them a 3-1 lead as Villarreal come to Mestalla.
Arsenal's clean sheet and Benfica's four-goal salvo against Franfurt ensure they are both well represented.
Benfica's João Félix, 19, was the star of the night, while Arsenal, Chelsea and Valencia made positive starts.
The week's most comfortable winners, Liverpool are especially well represented in our Fantasy Football best XI.
Cristiano Ronaldo has passed 125 and Lionel Messi is over 100, but who else has reached a half-century?
Barcelona hold a narrow advantage at the halfway point of the tie after victory at Old Trafford.
Cristiano Ronaldo has passed 125 and Lionel Messi is over 100, but who else has reached a half century?
Juventus and Ajax meet again in Turin with their quarter-final in the balance after they shared a 1-1 draw in Amsterdam.
A fine David Neres goal cancelled out Cristiano Ronaldo's header to leave this tie delicately poised heading to Turin.
Cristiano Ronaldo has reached 125 goals in the UEFA Champions League, with only Lionel Messi within 50 of that mark.
Callum Hudson-Odoi made his full England debut before his first Premier League start; UEFA.com has the lowdown.
The 1996 final is replayed in Amsterdam on Wednesday as Ajax welcome Juventus for their first leg.
Manchester United need to turn around their fortunes against Barcelona as they welcome them for Wednesday's first leg.
It is advantage Spurs courtesy of Heung-Min Son's goal and Hugo Lloris' penalty save.
Eintracht Frankfurt are one game from equalling Atlético's competition-record unbeaten run and Chelsea are close behind.
As he prepares for his first game at Old Trafford, Sergio Busquets recalls his two final encounters with the Red Devils.
Iker Casillas remains out in front although Cristiano Ronaldo is threatening to catch his one-time team-mate.
"We can show everyone that we are just as good as them, or even better," the midfielder Frenkie de Jong tells UEFA.com.
Liverpool have one foot in the UEFA Champions League semi-finals after a 2-0 win against Porto.
Premier League leaders Liverpool welcome suspension-hit Porto for Tuesday's quarter-final first leg.
Full details as Tottenham welcome Manchester City to their new stadium for an all-English quarter-final.
Barcelona meeting Manchester United in Europe means another entry into their string of classic ties.
"If it's not this year, I think it will be next year," said Riyad Mahrez as he yearns for his first UEFA Champions League winners' medal.
"I'm trying to give everything I've got so I can lift the trophy one day," says Liverpool's Senegalese forward.