Photo taken at a Wayang Kulit show (traditional Javanese shadow puppet theatre) in a Museum in Yogyakarta (Java Island, Indonesia).
The Wayang show was accompanied by a Gamelan traditional percussion orchestra.
For more information about Gamelan, read en.wikipedia.org/wiki/Gamelan
For more information about gongs, read en.wikipedia.org/wiki/Gong.
For more information about Gamelan traditional percussion musical ensembles, read en.wikipedia.org/wiki/Gamelan