The auditorium at Crocus City Hall was about three-quarters full, with the crowd waiting to see Picnic, a band popular since the Soviet days of the early 1980s. But the concert was sold out in the 6,200-seat hall, so some of the audience was still likely getting food or were shedding their heavy coats in the cloakroom. Moscow Terror Attack: How the Deadliest Attack on Russian Soil in Years Unfolded Over the Weekend.