Photo = Lim Mija from Sobaeksan Wildflower Research Center

Danyang-gun County, Chungcheongbuk-do Province | June 14, 2024

Fireflies illuminate Ondalsanseong Fortress in Yeongchun-myeon Township of Danyang-gun County, Chungcheongbuk-do Province. Highly sensitive to water quality, light, contaminants and environmental pollution, the insects are known as a leading species indicating a clean area.