Hailing from Croatia, classically trained musicians Luka Šulić and Stjepan Hauser quickly rose from the conservatory halls to become YouTube stars in 2011 (via “Smooth Criminal”) and then world-famous recording artists. 2CELLOS bridge the gap between rock, pop, and classical by finding pleasing harmonies in recordings of popular tunes, such as their adrenaline-filled “Eye of the Tiger” and their sentimental-yet-adventurous “Game of Thrones Medley.” Their classical roots, however, are close to the surface: Hear their wistful, richly intoned reading of the “Schindler's List Main Theme.”