A special report from Washington, where thousands of students are marching in favour of stricter gun control laws. BBC Trending has been following three student activists affected by gun violence. The students are demanding bans on powerful semi-automatic rifles and a comprehensive raft of measures to stop school shootings. Vladimir Putin has won a second consecutive and fourth overall term as the Russian President with official polling results from the election showing he received over 76% of the vote, with a total turnout of 67%, but there were also widespread allegations of irregularities including inflated turnout figures. We take a closer look at the election data from Russia to see if these complaints have merit. Machines are merging into our lives in ever more intimate ways. They interact with our children and assist with medical decisions. Cars are learning to drive themselves, and algorithms can determine who gets government assistance and help suggest our romantic partners. But machines learn from the instructions humans give them. So, how do we know that the technology we are creating is going to do the right thing? Sandra Kanthal reports.