Ukrainian twin sisters dive into the unknown ahead of Paris Olympics

Air raid sirens wail as artistic swimmers Maryna and Vladyslava Aleksiiva rest on their only free day from their rigourous training program in the eastern Ukrainian city of Kharkiv.

They are the stars of Ukraine's Olympic-medal-winning team, which returned to the city to train for next summer's Paris Olympics, despite its proximity to the front line and being regularly shelled.