Bauklötze staunen
to be utterly amazed; to gawp in astonishment
Origin
The origin is probably Berlin slang around 1920: from 'Jlotzoogen' (goggle-eyes, big astonished eyes) it became, via 'Jlotzen staunen' and a reinterpretation, 'Bauklötze staunen'. The explanation is considered plausible but not fully certain.
Building blocks
Words in this expression
Examples
Als sie ihr neues sah, staunte sie Bauklötze.
When she saw her new car, she was absolutely gobsmacked.