"What's the best stadium in European football?" was the question last week when Manchester United fans visited Madrid. For some, the towering 80,000 seater Bernabeu shaded the bigger Camp Nou. It's steeper, taller, with more tiers.
Stadiums were judged from the outside too, the location and the history. In America, history is what makes an old ballpark like Fenway Park or Wrigley Field so popular among the bigger, newer, corporate domes. Even the new builds try and ape the designs of the 1920s.
In England, Fulham's Craven Cottage remains a favourite precisely because it's not an identikit out-of-town bowl differentiated by the colour of its seats.
In subsequent discussions about football stadiums, Milan's Giuseppe Meazza - the famous San Siro - emerged as a rival contender. "It looks like it wants to fight you," was one assessment of the ground shared by both Milan clubs.
It will stage AC Milan v Barcelona on Wednesday night, the one permanent fixture at Milan amid the continuous upheaval. Just two of the Milan players who played against Barça last season started their game at the weekend. Viewed from the outside, the giant red girders and circular stairs of the San Siro win.
Camp Nou is scruffy and sunken, with a part pebbledash exterior like a 70s council house; the Bernabeu is better, but still all exposed concrete.
They are the three venues which top polls, but there are some serious rivals.
The new Wembley is viewed by UEFA as the finest in Europe. It boats a vast 90,000 capacity and more executive facilities to keep an army of prawn sandwich eaters and city boys happy. It's not yet loved though, because fans still romanticise about that ashtray once adjoined to the Twin Towers, while the new Wembley feels just that, new.
It's superb though, but attachment to a stadium is bundled up with the great events which take place there over bricks and mortar. Once attachments have been formed, they're hard to shift, as Liverpool and Everton fans point out if suggestions are made for them to move or share a new stadium.
Old Trafford was another UEFA five star stadium – one of 29 on a list used by UEFA up to 2006 when they redrew the rules. No stadium with a capacity of less than 60,000 has staged a Champions League final since then, but which is the best?
Old Trafford is England's biggest club stadium, and, though hugely impressive, the roof swoops too low to give it the same impact of the best. Like Arsenal's Emirates or Newcastle's whatever it is called these days, it's also a true football ground, free from an athletics track which make Olympic Stadiums in Athens, Berlin, Istanbul, Rome, Moscow, Barcelona and Seville, however wonderful, not perfect for football.
Just as Brazil is rebuilding 14 stadia ahead of the 2014 World Cup, so countries which have staged past events benefited from a surge in stadia investments.
Portugal may be among the poorest countries in Western Europe, but it has some of the best venues after Euro 2004, including the bonkers one in Braga, which has two stands, a rock face behind one end and a forest at the other.
Most of the German stadiums built for the 1974 World Cup finals were rebuilt for the 2006 edition, minus the running tracks. Munich's futuristic Allianz Arena is a groundbreaking as the original Olympic Stadium was in 1972 and was rightly awarded the Champions League final last year.
The new giant or expanded grounds in Hamburg, Dortmund, Hanover and Monchengladbach - in fact most German cities with a Bundesliga team - are magnificent, but they also incorporate terracing.
Grounds like the Stade de France were built for France 98, epic venues like Marseille's Velodrome remodelled. It's undergoing another expansion, up to 67,000 with an imposing new 'roof of light' for Euro 2016.
That would have been developed anyway, for Marseille average 50,000. The same applies in Glasgow, which is particularly well served by fine venues: Hampden, Celtic Park and Ibrox. Istanbul, too, has three top class venues, two of which are among the noisiest in world football most weeks.
No country has more than Spain's five stadiums on the 2006 list – sure to be seven when Athletic Bilbao and Valencia complete their new homes. Unlike at Valencia where the work has stopped, progress at Athletic's new 53,000 cathedral continues apace and it opens in September.
Being newly built is only one facet. Architectural design also counts. The imposing red brickwork exterior of the shared Stadio Luigi Ferraris in Genoa not only made it an urban art-form when it opened before Italia 90, but also the inspiration for Preston's developed Deepdale.
The Camp Nou and the Bernabeu remain the best. They're steeped in history of the finest players in the world, they attract vast crowds and they're huge.
Both are to undergo redevelopments, with Madrid aiming to 'wrap' the Bernabeu and increase the capacity by 10,000 seats to 90,000. Despite looking like it can't go any higher, architectural minds are trying to find a way.
Barcelona plan a bigger project. They were so impressed by the new 100,000 capacity Dallas Cowboys stadium in Texas in 2010 they considered copying it – though without the pink dressing room for cheerleaders.
Prior to that, plans were announced around the stadium's 50th anniversary in 2007 for Sir Norman Foster to expand the capacity to 106,000 by increasing the height of the main stand, then covering and cladding the uninspiring outside of Camp Nou in a Gaudiesque terracotta exterior.
It would have been a new architectural icon for a city already stuffed with design classics, but the project never broke ground and plans will be shelved by the austere new board who will struggle to justify the anticipated €250 million cost.
It will be built, just not yet. Some of the world's best stadiums are outside Europe. We'll come to them in the future, but for now, what's your favourite in Europe?