After the last elections in Russia, mass protests against vote-rigging led to violent clashes in Moscow. They were the biggest challenge Vladimir Putin has ever faced to his rule. Four years on and some demonstrators are still serving long prison sentences, the laws on protesting have been tightened and arrests continue. As Russia gears up for its next elections, Our World meets some of those caught up in the 2012 protests and asks what their experiences tell us about President Putin's Russia.