German champions Bayer Leverkusen will celebrate their historic season alongside fans on May 26 with an open-top bus parade and a stadium party, the club announced on Monday. The event comes a day after the German Cup final, where they face second tier Kaiserslautern in Berlin. Xabi Alonso’s side could also be in the Europa League final on May 22 in Dublin. Even if the so-far unbeaten side stumble in the Cups and miss a remarkable treble, the party will go ahead to celebrate their first ever Bundesliga title and run of at least 48 games undefeated across all competitions. Around 40,000 free ti…