Rio's nights in shining water

The 2016 Rio de Janeiro Olympic Games will force swimming's elite to adopt some nocturnal habits as preparations are stepped up in the coming months in the race for gold.

The world championships finished on Sunday in Kazan, Russia, as the US again topped the swimming events with 23 medals, followed by Australia (16), China (13) and Britain (nine).

But for coaches and swimmers alike, Kazan is already forgotten. It's all about Rio from now on - and lots of late nights.