火车站弹钢琴2.0 🎹

几天前翻手机翻出了这个视频——几年前我路过伦敦时在圣潘克拉斯火车站演奏了一曲。
你们猜得出我弹的是哪首曲子吗？

I came across this video in my phone archives a few days ago—stopping in London a couple of years ago and trying out the piano at St Pancras Station. 
Can you guess the piece?