Photos have surfaced of Canadian Prime Minister Justin Trudeau wearing brownface makeup. The World's Rupa Shenoy looks into the history of brownface and blackface in Canada, and puts the photos in social context. Plus, the drive to thwart diseases like malaria and dengue by altering the genes of mosquitoes. Scientists warn, however, that the work needs monitoring to avert unintended consequences. And what to expect when the United Nations holds a special climate summit next week.