Lights around the globe will be turned off on Saturday night as part of an annual grassroots movement to shine light on environmental issues. Millions of people participate in Earth Hour, which happens in Denver from 8:30 p.m. to 9:30 p.m. Hundreds of iconic spots around the planet, including the Eiffel Tower in Paris and Empire State Building in New York City, have participated in the event. In Denver this year, Denver International Airport, as in years past, will turn out the lights on the airport’s giant blue “Mustang” statue, as well as dimming the “Shadow Array” artwork at the hotel and transit center, DIA said in a Friday news release. “Denver International Airport works hard to be a sustainability leader within the aviation industry,” Scott Morrissey, DIA’s senior director for sustainability, said in the release.