Who are Alexei Navalny’s fellow key Russian dissidents?

The sudden death of Russian President Vladimir Putin’s most formidable antagonist has left an open wound in Russia’s political opposition.
Alexei Navalny, 47, was the Kremlin’s best-known critic at home and abroad. Before he died in a penal colony on Friday, the anti-corruption crusader, protest organiser and politician with an arch sense of humour became the subject of an award-winning documentary. His channels on YouTube had millions of subscribers.