This pair of doors comprise a bronze casting of the 95 Theses which Martin Luther posted on a previous door in this location of the Castle Church in Wittenberg, Germany. The date: 31 October 1517, usually deemed the beginning of the Reformation.
OK, so what? You can find this out on Wikipedia.
I went with my family on a pilgrimage to Europe in 2017 - 500 years later - and on Sunday 27 August we attended a church service here. Then my daughter - at the time aged 14 - posed with a hammer at these very doors, to the bemusement of the clergy greeting exiting worshippers!
Should mention this is a big deal for me because I am a Lutheran pastor.