The design was conceived as a response to what seemed like a battle to be lost.
The European Central Bank was going to build a skyscraper on the scene of the crime - next to The Grossmarkthalle. The two building creating a X and a Y axises in a gigantic Cartesian coordinate system. One embodying the history, the other one the future. The horisontal; Grossmarkthalle (a historic landmark), pointing backwards, and the vertical; the ECB-highrise pointing upwards - towards the future.
They were going to build a giant monument in glass and steel, to celebrate money and progress on the site of Nazi violence and hate. The designteam realised that no grand gesture build in the memory of Frankfurt jews could possibly win the battle for attention with these giants. And it would be like raising a tombstone - a ridiculously small one, that would give the impression that we were trying to bury the memory of holocaust.
Building nothing was the only possible option...to do the absent monument.