The concert was held in a newly liberated area with ISIS nearby. The concert, "Pray for Palmyra: Music Revives Ancient Ruins," was dedicated to victims of the terrorist group. The concert itself was almost an hour long and featured music by Sergei Prokofiev, Johann Sebastian Bach and Rodion Shchedrin.
http://edition.cnn.com/2016/05/05/middleeast/syria-palmyra-russia-concert/index.html
