Customizable atomium model: the default values reflect the real dimensions of the Brussels Atomium (scale 1/1000). You can modify the sizes, and choose to build a model of the Atomium building or just the iron atom.

The model is probably not very suitable for printing, it will require lots of support material. I'm planning to make an alternative version with separate parts, for easier printing.

UPDATE: there seemed to be a problem in the Customizer, it appears not to accept decimal values. Changed parameters to integer values, now it works.