The UEFA Champions League semifinals get underway on Tuesday, Apr. 29 with Arsenal taking on Paris Saint-Germain for the second time this European campaign.

Treble watch continues for Paris Saint-Germain and Barcelona, both of whom have already collected their first trophies of the season and are perhaps the most formidable candidates

How does it work?Thirty-six sides entered into the new "league phase" and now just four remain with a month-and-a-half to go in the UCL campaign.Barcelona, Paris Saint-Germain, Arsenal, and Inter Milan are through to the semifinals,