Red Bull Flugtag held in Dublin, Ireland

Participants drive a flying machine during the Red Bull Flugtag at Dun Laoghaire Harbour in Dublin, Ireland, May 20, 2018. Red Bull Flugtag, or "Red Bull Flying Day", in which competitors attempt to pilot home-made, human-powered flying machines, was held in Dublin on Sunday, attracting tens of thousands of local people. (Xinhua/Zhang Qi)