An acappella concert is held at the Gengsu Theater in Chongchuan district, Nantong, East China's Jiangsu province, on June 18. Key Ensemble, a choir group from Finland, left an unforgettable impression on the local audience after performing 16 songs. [Photo/VCG]

A singer performs at an acappella concert held in Chongchuan district, Nantong, on June 18. [Photo/VCG]

Key Ensemble, a choir group from Finland, gives an acappella performance in Chongchuan district, Nantong, on June 18. [Photo/VCG]