Why super-sized and politicised World Cup comes at a cost

"Simply the greatest event that humanity, that mankind, has ever seen".

The words of Fifa president Gianni Infantino when hailing this summer's World Cup across the United States of America, Mexico and Canada.

Never afraid to hype football's showpiece event, the head of the world governing body has portrayed the first pan-continental version as the most inclusive, welcoming and unifying to date.

The most politicised, for instance. And the most expensive. Potentially the hottest, or the most polluting. Certainly the most lucrative for Fifa.

Whatever one's perspective, it seems certain that away from the on-field spectacle, this super-sized World Cup could be among the most contentious ever.

From controversy over the costs to fans, the impact of geopolitics and immigration policies, to security, extreme weather, sustainability and the role of US President Donald Trump, it inspires trepidation as well as excitement.

So what will be the principle issues? How did we get here? And what is at stake?

As the eyes of the footballing world focus on Mexico City before Thursday's opening match, the co-hosts provide a vivid snapshot of what makes the next few weeks so compelling and challenging.