Art Festival... In the subway?!

Last night, I was getting off the subway in Seomyeon (the center station of Busan) and heard someone singing and people clapping along!  Hmm?  What could it be, I thought?!   I walked towards the music and found this - The Humetro Art Festival!

Yes, an art festival in the subway!  Only in Korea!  Last night's featured art was:
SINGING! 

Can't wait to see what I stumble upon next in this creative country!