The inside story of the Allianz Arena, Champions League Final venue

We now know the contenders for the Champions League Final on Saturday 19th May: Chelsea and Bayern Munich. Bayern will have home advantage, because back on 29th January 2009 the 2012 final was awarded to the Allianz Arena, which they own but share with neighbours 1860 Munich.

Designed by architects Herzog & de Meuron, the stadium began construction on October 21st 2002 and was officially opened on May 30th 2005. It's a fascinating stadium: have a look.

The main entrance to the stadium is along the Esplanade. Visitors can access the Arena from the nearby Fröttmanning underground station, the coach parks or the multistorey car parking. The parking facilities under the Esplanade are EuropeâÂÂs biggest underground car park, offering spaces for approximately 9,800 cars. There are spaces for a total of 350 buses â 240 to the north of the Arena and 110 in the south.

The roof of the Allianz Arena consists of 2,874 air cushions and has a total surface area of 64,000 square metres. The foil is only 0.2 mm thick and up to 98% UV-permeable. It is, it says here, the worldâÂÂs biggest roof made of foil. Each cushion has a surface area of approximately 35 square meters, although none of the honeycombs has precisely the same shape. The honeycombs are made of ethylene tetrafluoroethylene, as if you couldn't guess.

Giant fans underneath the stadium plump up the cushions, like a good house-cleaner. If the blower fails and water collects during the resulting cooling process, a clever little valve opens at the lowest point so that the moisture can flow away before the mass of water overloads the roof construction. Which would suck.

If snow settles on the roof during winter - not likely in May, but bear with us â a total of 12 pressure sensors measure the snow and trigger a pressure increase in the cushions to balance out this load.

The membranes, one-thirtieth of the weight of glass, have a self-cleaning coat and are ventilated continuously.

The two 'Allianz Arena' signs are up to 4m high and are made of steel, sheet metal, aluminium and transparent plastic. Each letter weighs between 250 and 500 kg. More than 100,000 light-emitting diodes (LEDs) have been installed in each sign and they only require about 20% of the power used by conventional lighting, so that's nice.

Eye-pleasingly, the Arena can be lit up in different colours to mark the teams who are playing there â so when Bayern are at home it's lit in red, for 1860 it's blue and for Germany games it's white. The light can be changed within the space of two minutes. Here it is in Chelsea blue:

â¦and in Bayern red:

Just for chuckles, and not to antagonise Pep and Jose, but here's what you could have won (besides the Champions League): the stadium in Barcelona and Real Madrid livery.

The stadium has a top capacity of 69,901 â although that figure includes standing areas.

There are 66,000 seats, and as usual for Champions League games this may be slightly restricted by segregation.

There are three tiers, the lower tier seating 20,000, the middle seating 24,000 and the upper 22,000.

Herzog & de Meuron designed a new type of seat specifically for the Arena. Unlike in many other stadiums, where standard seats differ from box seats, the three different forms of seating used in the Arena (standard folding seat, VIP seat and box seat) are of uniform size and appearance, with silver coating. Each individual seating space was hand-marked, down to the last millimetre, before the first seat was installed, because the Arena is curved rather than rectangular.

There are four changing rooms â one for each of the 'home teams' (Bayern and 1860) and one each for their respective opponents. There are also two changing rooms for the officials. Curious. 

Each changing room "boasts" (weird word, that) 22 lockers and 12 showers. You can make your own joke up there.

Above is the mixed zone, where the world's media will attempt to pigeon-hole the winners and losers. And below is the tunnel from which the protagonists will emerge. May the best team winâ¦