2016 Rio Olympics - Swimming - Victory Ceremony - Men's 4 x 100m Freestyle Relay Victory Ceremony - Olympic Aquatics Stadium - Rio de Janeiro, Brazil - 07/08/2016. Michael Phelps poses with his gold medal as he celebrates with his team. REUTERS/Marcos Brindicci

2016 Rio Olympics - Swimming - Victory Ceremony - Men's 4 x 100m Freestyle Relay Victory Ceremony - Olympic Aquatics Stadium - Rio de Janeiro, Brazil - 07/08/2016. Michael Phelps (USA), Ryan Held (USA), Caeleb Dressel (USA) and Nathan Adrian (USA) of USA pose with their medals. REUTERS/Stefan Wermuth

2016 Rio Olympics - Swimming - Final - Men's 4 x 100m Freestyle Relay Final - Olympic Aquatics Stadium - Rio de Janeiro, Brazil - 07/08/2016. The USA team celebrates after winning. Picture rotated 180 degrees REUTERS/Athit Perawongmetha

2016 Rio Olympics - Swimming - Final - Men's 4 x 100m Freestyle Relay Final - Olympic Aquatics Stadium - Rio de Janeiro, Brazil - 07/08/2016. Michael Phelps (USA) of USA reacts after his team won the gold. REUTERS/Marcos Brindicci

2016 Rio Olympics - Swimming - Victory Ceremony - Men's 4 x 100m Freestyle Relay Victory Ceremony - Olympic Aquatics Stadium - Rio de Janeiro, Brazil - 07/08/2016. Nathan Adrian (USA) of USA cries next to teammate Michael Phelps (USA) as they pose with their medals. REUTERS/Stefan Wermuth

2016 Rio Olympics - Swimming - Final - Men's 4 x 100m Freestyle Relay Final - Olympic Aquatics Stadium - Rio de Janeiro, Brazil - 07/08/2016. The USA team celebrates after winning. REUTERS/David Gray

A container box is loaded on to a truck at a port in Rizhao, Shandong province, August 12, 2015. REUTERS/Stringer

2016 Rio Olympics - Swimming - Victory Ceremony - Women's 100m Butterfly Victory Ceremony - Olympic Aquatics Stadium - Rio de Janeiro, Brazil - 07/08/2016. Sarah Sjostrom (SWE) of Sweden holds her national flag after winning the gold. REUTERS/Dominic Ebenbichler