Arsenal hosts Paris Saint-Germain on Tuesday in the semifinals of the UEFA Champions League. Here is what you need to know before the kickoff of the first leg.

The Champions League is down to four, with one club from four of Europe’s top five leagues represented in the semifinals. PSG the champions of France, takes on Arsenal in London, while Barcelona hosts Inter Milan during a chaotic time for both clubs.

Arsenal and Paris Saint-Germain have each knocked out one of the favourites for the competition and meet in a blockbuster UEFA Champions League semifinal.