Participants dressed as alien characters from the film “Mars Attacks!” launch their flying contraption during the Red Bull Flugtag event in Hong Kong on November 27, 2016. The Flugtag – which means “flying day” in German – is a competition in which teams in fancy dress attempt to pilot human-powered, home-made flying machines off a platform into water. (Photo by Tengku Bahar/AFP Photo)





Competitors ride a home-made vehicle without an engine on a downhill track in the Red Bull Soapbox Race in Santiago, Chile, November 27, 2016. (Photo by Jonathan Faus/Reuters)





A competitor rides a home-made vehicle without an engine on a downhill track in the Red Bull Soapbox Race in Santiago, Chile, November 27, 2016. (Photo by Jonathan Faus/Reuters)





Competitors ride a home-made vehicle without an engine on a downhill track in the Red Bull Soapbox Race in Santiago, Chile, November 27, 2016. (Photo by Jonathan Faus/Reuters)





Competitors ride a home-made vehicle without an engine on a downhill track in the Red Bull Soapbox Race in Santiago, Chile, November 27, 2016. (Photo by Jonathan Faus/Reuters)





Competitors ride a home-made vehicle without an engine on a downhill track in the Red Bull Soapbox Race in Santiago, Chile, November 27, 2016. (Photo by Jonathan Faus/Reuters)





Competitors ride a home-made vehicle without an engine on a downhill track in the Red Bull Soapbox Race in Santiago, Chile, November 27, 2016. (Photo by Jonathan Faus/Reuters)