Today marks the 50th anniversary of the Munich air disaster, when Manchester United players and officials returning from the European Cup quarter final in Belgrade, crashed at Munich airport.
To Mancunians of my age and older, it is a central part of our identity. Those who mock the disaster, or United's desire to commemorate it, are attacking far more than a rival football club. They attack our history and our personal identity.
In 2005 I visited the Red Star Belgrade club museum. In there they have a picture of the United team taken prior to kick off, and a priceless card signed by all the players prior to the game.
I think United should have marked the anniversary by playing a charity game in Belgrade, with proceeds divided between Munich survivors (who were not always well treated by the club) and charities working for reconciliation in the former Yugoslavia. Finding time for such a match in the fixture schedule would not have been easy, but United did find time last month to visit one of the most oppressive countries in the world, Saudi Arabia.
Still, I am hoping Sunday's match versus City will be a fitting tribute.
There are various Munich tribute sites. One of the best is the Munich 58 website.