The city of Mariupol lies on the Azov Sea, next to the front lines of Ukraine’s war against Russian-backed rebels. The conflict has touched everyone’s lives as the danger of an escalation looms over the city. Moscow’s continued detention of 24 Ukrainian sailors seized just offshore in November underlines the threat. Faced with such challenges, how do the people here view Sunday’s presidential election, and who holds the key to ending the conflict? Henry Ridgwell reports from the city.