The wild life of Alexey Navalny, who challenged Putin and appears to have died in prison

• Russian dissident Alexey Navalny became President Vladimir Putin's biggest opponent.
• He campaigned against fraud and corruption and ran in elections before he was jailed.
• On Friday, Russian officials said he had died suddenly in prison.

Alexey Navalny, an outspoken critic of Russian President Vladimir Putin, has died in prison, according to Russian officials.

Navalny, 47, had been a thorn in Putin's side for years — first as an anti-corruption blogger, and later as an independent politician running and campaigning in local and national elections.