25,000 fans sing fervently on Dortmund's legendary south stand, jumping around wildly arm in arm.
These pictures have long been known from the Bundesliga.
But from the coming season, the "yellow wall" can finally unfold its full force in the European Cup.
The European Football Union (UEFA) is breaking a taboo after decades, the seat requirement is being softened and standing room is returning.
This was decided by the UEFA Executive Committee on Wednesday.
“This is great news.
Standing room is an important part of our football culture,” said Hans-Joachim Watzke, CEO of Borussia Dortmund.
In recent years, BVB has worked intensively behind the scenes to allow standing room grandstands in international competitions.
"I would like to sincerely thank the President of UEFA, Aleksander Ceferin, and the Executive Committee of UEFA for their support," said Watzke. "I ask all fans to use this opportunity responsibly next season." Dortmund's stadium capacity in the Champions League will thus increase by more than 15,000 from the previous 66,099 places to 81,365 places.
25,000 people will find space on the largest standing room grandstand in Europe.
Along with England and France, Germany is part of the pilot project longed for by many football romantics.
The fans are also allowed to stand again in the Champions League, Europa League and Conference League, although the finals in all three competitions are not part of this regulation.
Union Berlin could also be a big winner.
There is more than 18,000 standing places at the Alte Försterei, but fewer than 4,000 seats.
That's why an alternative to the Hertha Olympic Stadium was unavoidable up to now, "real" European Cup home games may now be possible.
In principle, standing room is provided for home fans.
The respective host decides whether guest fans are also allowed to stand.
The seat requirement was in the 90s, among other things, a reaction to the Hillsborough disaster in 1989 with 97 dead.
For international matches, the seat requirement that has been in place since then continues to apply.
If the "observation program" is successful, the regulation could be extended both regionally and over time, UEFA wrote.
The softening could also come sooner or later for international matches.
Spanish and Italian clubs could have participated in the testing phase now, but the qualified teams do not have stadiums with suitable seats.
Most recently, England, the motherland of football, reopened all professional stadiums for “safe standing” after a six-month test phase at selected clubs.
"This isn't the old grandstand anymore, this is a whole different world and safety is paramount," said England Secretary of State for Sport Nigel Huddleston.
Many fans hailed this as a return to basics.
Thanks to improved video surveillance, in the future, even with standing room, you will “know exactly who is in each individual seat and in each individual area,” emphasized Huddleston.
UEFA has now also recognized the advantages of standing room - now everything depends on the implementation of the supporters.