Question: what's black and yellow and blue all over? Answer: the Revierderby, the Bundesliga's biggest rivalry and one of the world's most eagerly anticipated match-ups. The Ruhr district is always ready to rock when Borussia Dortmund face Schalke with bragging rights and more on the line.
If that does not set the scene for you, here are 10 things about the mother of all derbies...
1) Kohlenpott order
Dating back to 1925, the Revierderby is a contest steeped in tradition, regional politics and fierce local pride. Coal versus steel, Royal Blue against Black-and-Yellow, underpinned by a long-standing game of oneupmanship for good measure: Schalke against Dortmund is a fixture like no other in world football. Only 32 kilometres separate the two clubs, both situated in the country's industrial heartland, the Ruhr district, and while a number of other professional teams hail from the wider Ruhr region, they have to make do with the tag 'minor Ruhr derby' for their various head-to-heads. Other than their proximity, there was no particular trigger for a rivalry which, if anything, has only intensified over the years for two sets of fans who basically like nothing more than to put one over on their neighbours. The fixture has become one of the most passionately contested encounters anywhere in the world game and means more to each set of fans than any other meeting on the football calendar.
Watch: A Revierderby history from 1 to 94!
2) North/South divide
This game is firmly situated in Germany's Ruhr area, but extrapolated from the geographical significance of this fixture is a rather unique north/south divide. Legend has it that Dortmund moved their hardcore fans from the north side of their former Rote Erde Stadium to the south side of their new Westfalenstadion, when this opened ahead of the 1974 FIFA World Cup, since Schalke's Parkstadion, which had been opened earlier, saw their hardcore fans allocated the north stand. Not wanting to have anything in common with their bitter local rivals, Dortmund therefore ensured their famed Südkurve would be the home for their vociferous fans.
3) Early meetings
Dortmund took eight of the first 10 derby dates of the Bundesliga era, before Die Knappen finally struck gold on 20 April 1968 with their first win over Dortmund since 7 September 1963. Another Schalke success on 4 March 1972 proved an even bitterer pill to swallow for Dortmund, whose subsequent relegation ensured it would be another three years before the Ruhr powerhouses could renew acquaintances. True to form, it was Dortmund who restored Kohlenpott order upon their return to the top flight as Lothar Hubner gave Dortmund their first victory over Schalke in nearly 10 years on 5 November 1977.
4) Barking mad
In 1969, police with dogs tried as hard as they could to keep fans from overspilling onto the field. One German Shepard dog named Blitz became a little over-zealous, though, and took a bite out of Schalke player Friedel Rausch. Forget the magic spray, though – Rausch was given a tetanus shot and was able to finish the game. As it later transpired, the dog did not belong to the police but had in fact been brought in by a Dortmund fan who had pretended to be a police officer to gain access to the game.
5) Revier revenge: part 1
In the reverse fixture, Schalke president Günter Siebert found a novel way of gaining revenge. He paid a visit to the local zoo and loaned out a lion for the day. He patrolled the pitch with the lion on a lead as fans saw the funny side of the incident earlier that season, and fortunately the lion did not bite anybody that day. Nor did any dog, since the Bundesliga had responded to bite-gate by ordering all dogs to wear a muzzle. The ordinance did not apply to lions, however.
Watch: The biggest moments in the history of the Revierderby
6) Title heartache
Returning to the Bundesliga after their 1987/88 relegation, Schalke and former Dortmund midfielder Ingo Anderbrügge set the tone with the opening goal at the former's old Parkstadion home just two minutes into the August 1991 tie. Dortmund managed to draw level before half-time, but were left reeling after the restart as the Royal Blues cruised to a stunning 5-2 win, with Dortmund ultimately losing out in the title race to eventual Bundesliga winners VfB Stuttgart on goal difference.
7) Title heartache: part 2
That was not the first incidence of this being a title-defining derby. Dortmund's derby win in 2007 was perhaps the sweetest of them all. On the penultimate day of the season, Schalke went into the Revier clash as league leaders, a point clear of second-placed Stuttgart. The Swabians won their Matchday 33 encounter in Bochum, but Schalke went down at the Signal Iduna Park with Alexander Frei and Euzebiusz 'Ebe' Smolarek the party-poopers, Dortmund effectively ruining their rivals' hopes of lifting the Bundesliga title for a first time.
8) Memorable debuts
We all know Robert Lewandowski as the most prolific non-German goalscorer in the history of the Bundesliga, but who can remember his first-ever goal in the German top-flight? Yes, it came in a Revierderby. It was his third substitute appearance in a Black and Yellow shirt, and one he and Dortmund fans will never forget as he struck in a 3-1 win at the Veltins Arena – the first goal in a prolific love affair with German football and his first of 103 for Dortmund. Jürgen Klopp's first derby was another dramatic occasion.
It was only his fourth game on the Dortmund bench and Schalke came to the Signal Iduna Park on 13 September 2008. 2-0 down at half-time, things got even worse when Heiko Westermann made it three. Midway through the second half, Klopp's reign as Dortmund coach was getting off to perhaps the worst possible of starts until half-time substitute Alexander Frei took matters into his own hands. He set up Neven Subotic and then got his own name on the scoresheet before Dortmund earned an 89th-minute penalty. Klopp did not witness that penalty as he looked the other way, launching himself into an exuberant touchline celebration only when the crowd roared.
9) Mother of all atmospheres
As breathtaking as the atmosphere may be at most Bundesliga matches, the deafening backdrop of the Revierderby truly sets itself apart as one of a kind, reaching its climax at kick-off when followers of both clubs really make their presence felt through chanting, hoisting huge banners into the sky or performing elaborate choreographies. With the atmosphere adding to the electric nature of the encounter, it is only natural that the occasion should get to the players, with the Ruhrpott rumble traditionally being a heated affair to say the least. Ultimately, though, it is bragging rights that matter most come the final whistle at the end of an experience that football fans around the world should be putting on their bucket lists.
Watch: The greatest Revierderby ever - Dortmund 4-4 Schalke!
10) Mother of the mother of all derbies?
What was the mother of the mother of all derbies? Perhaps the 2017/18 edition in Dortmund, in which the hosts led 4-0 after just half an hour in front of a delirious Signal Iduna Park crowd. Job done? Think again! Schalke hit back in the second half and Naldo's 94th-minute header earned the Royal Blues a 4-4 draw. Or what about the time Jens Lehmann stole the headlines on 19 December 1997? The former Germany international rose to head home in the 90th minute in a thrilling 2-2 draw, in the process becoming the first-ever goalkeeper in the Bundesliga to score from open play.