Now is the time to fill the gaps in your knowledge ahead of the big kick-off - even some gaps you didn't know were there.

It's the best and worst, the biggest and smallest, the most and least of the 2018 World Cup.

The heaviest and lightest players

Inui floats like a butterfly

Proof that you can't take World Cup newcomers lightly comes in the form of Roman Torres, the Panama defender and, at 99kg, the heaviest player taking part in the tournament.

At the other end of the scale comes Takashi Inui. The Japan midfielder, who has been based in Europe for seven years and recently joined Real Betis, weighs 59kg.

The tallest and shortest players

Kalinic, sitting down to fit in frame

One keeper you're unlikely to see lobbed in Russia is Croatia's Lovre Kalinic. That's mainly because he's unlikely to play, given Danijel Subasic holds the number one jersey, but it's also because he stands at a towering 201cm tall.

It's a three way tie for the shortest player, with Switzerland's Xherdan Shaqiri, Panama's Alberto Quinterio and Saudi Arabia's Al-Shehri Yahya all at 165cm.

The oldest and youngest squads

Alex Iwobi, one of the fledgling Super Eagles

Who says the Panamanians will go home empty-handed? They've taken three accolades on this page alone. Head coach Herman Dario Gomez has selected the oldest squad at the tournament, with an average age of 29 years and eight months.

Nigeria have the youngest - their players are on average 25 years and 11 months old.

In terms of individual players, Egypt keeper Essam El-Hadary will be a World Cup record breaker should he play aged 45, while the youngest is Australia's very own Daniel Arzani, who is 15 days younger than fellow 19 year-old and Group F nemesis, Kylian Mbappe.

The largest and tiniest population

Brazil fans coat the Copacabana in Rio during the 2014 World Cup

With Neymar, Roberto Firmino and Neymar, Brazil have strength in attack - and as a nation of 207.7 million people, the fifth-highest population on Earth, they also have strength in numbers.

The population of Iceland, by staggering contrast, is just 334,252. When they tackle Argentina on 16 June, they will become the least-populated nation ever to contest a World Cup match.

Biggest and smallest country

Belgium add up to far more than the sum of their parts

A bit of a non-contest, this one. Russia is spread over 17,098,246 km². Australia ranks in a close third behind Brazil.

On the other hand, with a bit of squidging into shape, Belgium - the smallest competing nation by area at just 30,528 km² - would fit into Australia a frankly ludicrous 252 times.

Most widespread and locally-based squads

Iceland’s players are scattered all across Europe

With only defender Biker Mar Saevarsson playing club football in at home, Iceland’s squad is compiled of players plying their trade in 14 different nations.

That said, they’re all in Europe. The players of Egypt and Argentina are spread over four different continents, which is more than any other nation.

England are the only one of the 32 nations without a single player operating abroad. What's more, 16 players (70% of their squad) are based in London and Manchester.

With top talents Jadon Sancho and Chris Willock two of a growing number of Young Lions taking a chance abroad, however, the signals are that this won’t be the case in future tournaments.

The warmest and coolest host city

Rostov Stadium, the setting of Brazil’s opening match against Switzerland

The two host cities of Volgograd and Rostov lie 500km apart, and are sandwiched between Ukraine and Kazakhstan towards the south of the country. Both average highs of 26.6°C in June, which make them the warmest of the eleven host cities.

Brazil begin their tournament at the Rostov Arena (above) against Switzerland.

As the northernmost host city, St Petersburg, which will host seven games including a semi final and the third-place playoff, tops off at 20°C on average in June, which makes it the coolest. England and Costa Rice have set up base there.

The biggest and smallest Twitter following

In spite of the oversized headwear, Mexico are trending!

The Twitter account for the Mexican national teams, @miseleccionmx, has 5.79 million followers, which is just a little more than the entire population of Sydney. And Denmark.

With 307,000, the @Socceroos have some catching up to do, but that's more than a few other competing teams, and certainly more than Sweden and Costa Rica, who are apparently too cool for this social media thing and don't have a dedicated account for their teams at all.

The longest and shortest national anthems

Bryan Ruiz and Keylor Navas, in it for the long haul

Very important, this one. Make yourself comfortable when Costa Rica get going on their national anthem - some extensive YouTube research has revealed they’ll be singing loud and proud for around 1min 34 secs.

Saving their breath for, you know, the match are Saudi Arabia, done and dusted inside 32 seconds. That's just quicker than England’s 39-second musical burst of off-pitch national pride. Dash to make a coffee and you may well miss a goal.

Fair warning.