It's been three years since Vladimir Putin signed off on Russia's annexation of Crimea - a unilateral act which landed Moscow with a wave of sanctions from Europe and the United States. Last year, Russia started building a bridge across the Kerch Strait which separates the peninsula of Crimea from the Russian mainland. It's a colossal project and of great importance to Putin. Our correspondents report on the progress so far.
A programme prepared by Patrick Lovett and Laura Burloux.