The 2006 World Cup sees Germany showcasing some of the best football grounds in the world and their design gives a clue to what the stadiums of the future will look like.
A round shape creates a better atmosphere, research suggests
Globally, a new generation of sports stadiums are fast becoming an important symbol of the cultural and economic future of a city and country.
Germany is proud of its stadiums, with the jewel in the crown being the new Allianz Arena in Munich. Not only can it change colour, but architects say its shape and multi-panel roof are the key to the look of the grounds of the future.
Future grounds will be designed as bowls, with an abandonment of the idea of four stands surrounding a pitch, and with roofs. Crucially, they will also return to the heart of the cities, after many years of being sited outside the city.
"They will change, there's no doubt about it," said Rod Sheard, an internationally-renowned architect and leading expert on stadium design who worked with Sir Norman Foster on the new Wembley stadium.
"The big change that's happened in recent years, and will be a real change in the next 20, is that city planners have started to realise how important these buildings are in city centres," he told BBC World Service's Culture Shock programme.
Shape is key
The key experience for many architects planning the stadiums of the future is that of the Stadio Delle Alpi, built for the 1990 World Cup in Italy and now home to Turin clubs Juventus and Torino.
Despite Juventus being one of Italy's most famous and best-supported clubs, the Delle Alpi is very rarely above half full. Some of Juventus' less important fixtures have seen extraordinarily low attendances - in 2001, only 237 turned up for a cup game against Genoa.
Poor visibility, and the stadium's being sited some distance from Turin, are usually blamed.
Ellery says referees will need "cooler heads" in the grounds of the future
"Back in the 60s and 70s, they were felt to be 'bad neighbour' buildings and were pushed out of town, and disconnected from the transport infrastructure, meaning they had to be surrounded by a swathe of car parks," Mr Sheard said.
"People now realise that was a totally wrong model, and that these are great buildings to have in a city centre. That is pretty well recognised as the model for the future."
These grounds of the future will also be a rounder shape.
"The shape of the bowl is very important, not just for the game itself, but to give people better sight-lines to the game itself," Mr Sheard said.
"There's something about being part of a big crowd, and we've found over the years that the most successful stadiums are ones where people can see the crowd.
"You're not just going there to see the game. You want to see those other 90,000 people around you."
Roofs, such as those on the Millennium Stadium in Cardiff or the Amsterdam Arena, will also become more commonplace, as they help keep the sound of the crowd enclosed and reflect it back.
Professor Alan Neville, from Wolverhampton University, told Culture Shock that this is important because his research had shown that such a thing as "crowd power" - the role that noisy fans play in affecting a referee's decisions - really does exist.
He invited referees to participate in experiments in which they adjudicated on decisions while watching a Liverpool versus Leicester match. When the referees were able to hear the crowd, they favoured the home team by an extra 15%.
"It appears the noise of the crowd provides protection," professor Neville said.
"The home side is under penalised compared to silence."
Former referee David Elleray said that if future stadiums will reflect back even more crowd noise, referees in the future will need a "cooler head" to be able to "block out any extra noise".
Ironically, the Stadio Delle Alpi is to revert to a traditional model this summer, with much of the existing structure to be demolished and replaced with four stands, which will be closer to the pitch and, it is hoped, greatly improve the atmosphere.
Alan Tomlinson, Professor of Sport and Leisure Studies at Brighton University, said the Delle Alpi was an example of a team moving - in Juventus's case, from the popular Stadio Comunale - and not being able to keep its "cultural memory".
No greater capacity
Teams in the future risk doing the same if they are not careful, he added.
"The thing about football stadiums is they have to have a capacity to generate cultural memory, and do it as quickly as possible," he said.
"This is particularly interesting in the Arsenal case at the moment, where at the new Emirates Stadium there is a particularly strong sense of the club and city history, along with the modernity of the big-scale new thing.
Wembley will seat 90,000 - and not many grounds will seat more
"The genius is to have done it in the same neighbourhood. One of the problems about keeping cultural memory, or adapting it to a new stadium, is if the geographical and physical shift is too big."
However, it is likely that one thing future stadiums will not be able to do is seat any more people than the current maximum, around 90,000.
"In size terms, they're probably pushing their upper limits," explained Mr Sheard.
"That's purely a practical thing, in terms of the people in the back row not being able to see the game; it gets to the point where you may as well just stay at home and watch the television.
"So they won't get bigger in capacity but they will get bigger in all the activities that go on inside them."