I will never have time to write this in the day. It has many different parts and I will probably fail to connect them. But.
In Buda Castle, there's this room:

Yes, it's just full of doors standing there. Each blue door represents one of the ten chapters of
The Admonitions written by Saint King Stephen in 1015 to his son Emeric. These are a new installation; St Stephen's Hall, like much of the castle was destroyed in WWII.
Now say you are standing in front of those doors; and say you are at once yourself split into twins light and dark, somehow always together but each twin goes through a different door and sees a different...something. The light twin goes through a door and finds themself beside the Danube, a place of happy people dancing, lights on the water, shores twinkling pretty as the twilight rolls in and the music plays.
The dark twin goes through another door and finds themself facing 60 pairs of sculpted shoes on a silent far from twinkling shore. These are a memorial to some 23,000 people - around 20,000 of whom were Jewish - who were stood there and told to step out of their shoes by members of the fanatical fascist Arrow Cross Party, government of Hungary from 1944-45.
They shot all those people, whose bodies then tumbled into the Danube. The dark twin felt it, a struggling last breath, a clutching of the chest, the deep blue closing overhead.The light twin will not have this because she is determined to live in the real world. She pulls the dark twin out of the water, fighting upwards.
The light and dark twin together know the river is beautiful and entirely innocent. They can share a drink there, smile, dance to the music, hold both visions of the Danube, understand both are true. This sounds like a paradox and is; I don't think it is something achieved by trying, indeed I don't know how it is done, only that it is done.
Through another door, and suddenly the twins are at Zsimpla Kert, first and most famous ruin bar in Budapest.
After WWII, the Jewish Ghetto was unsurprisingly empty; the Soviets had come to Hungary with no intention of leaving. They crushed the Arrow Cross party, hunted down and hanged its leaders and, in a poetic echo of Hungarian collaborative deportations - something like 440,000 gone to places like Auschwitz - sent many of that party's members to gulag forced-labour camps. Sometimes even the light twin hear karma's cold laughter.
Understandably the Jewish folk who managed to get out were not inclined to return. The buildings became dilapidated because the Soviets were not interested or didn't have the money to look after them. Time passed, and in the late 1990s/early 2000s drinking rooms began to rise in the ruined buildings, graffitti scrawled, adorned with tat and random art. Now everybody loves them. This is a thing you can do as the twins; You can walk through at least two realities at exactly the same time, and it's fabulous albeit occasionally distressing/weird. Up at Buda Castle there's a room with many doors and no doorways. At Zsimpla Kert there are many doorways and no doors.

I don't know what it means, only that there is something there. The doors know, the twins know, the river doesn't know and the ruin doesn't care. I have no answer and know this to be an unsatisfactory incomplete telling. But it is true.