This is a photo of the men who sit on the board of Discovery Communications. The media firm, which holds a variety of cable networks including Discovery, TLC, and Animal Planet and proudly promotes its diversity and inclusion policy on its corporate webpage, is hardly the only major public company with an all-male board. Nearly 3 percent of S&P 500 firms have no women on their boards, according to a report released Tuesday by the nonprofit Catalyst and consulting firm EY. Twenty-four percent of S&P 500 boards have only one essentially token woman. Put more simply, about a third of the boards of the country’s biggest and most influential businesses are nearly devoid of women at the top.