The winners of the world's biggest picture competition, the Sony World Photography Awards, have been announced. American photographer John Moore took the top prize, the 'L'Iris d'Or', for professional photographer of the year for his work in capturing the Ebola crisis as it ravaged through Liberia. 

2015's competition saw 173,444 individual images from 171 countries battle it out for the prize. You can see a selection of some of the winners in the gallery below: