A butterfly stays on the head of a staff member at the exhibition "the Butterfly Conservatory" in the American Museum of Natural History in New York, the United States, on Jan. 17, 2018. "The Butterfly Conservatory" is an annual seasonal exhibition at the American Museum of Natural History, inviting visitors to mingle with up to 500 fluttering and iridescent butterflies among blooming tropical flowers and lush green vegetation. (Xinhua/Wang Ying)