Sixteen-year-old climate champion Greta Thunberg brought her global environmental message to the heart of the US government on Friday, telling her legion of supporters outside the White House: "Never give up." The Swede, who has inspired youngsters across the world with her call to arms, demanded action from the world's No. 1 economy and President Donald Trump, a climate change sceptic, as part of a demonstration kicking off two weeks of protest. She joined a few hundred people who shouted slogans and sang, but was careful to stay near the back, avoiding the limelight and questions from the media before finally addressing her supporters. She thanked the crowd and rallied the wider teen environment movement to keep up the pressure on polluters.