On October 11th, B1A4 held their 'B1A4 Road Trip 2014' concert in San Francisco, California, USA.

But before the day of the concert, the fans surprised B1A4 with a flash mob. On his personal Instagram, Baro uploaded the group photo above, and expressed his gratefulness towards the people behind the performance. 

He captioned the photo with, "Group picture with flash mob dancers. ThankU for the suprise!!! ThankU #sanfrancisco . ThankU@mnetamerica .