It's technically very difficult to create BEC's of atoms, using lasers to cool the atoms to near absolute zero, in a vacuum chamber, and it was only first accomplished in 1995, despite being predicted many decades before that. The atom, or molecule, BEC's so far created are, from what I've read, just big enough to be seen by the naked eye, with a little optical magnification. I didn't actually check what the maximum width achieved so far with BEC's, but is there any practical limit to how large an atom, or molecule, BEC could be? If technology wasn't an issue could it be an inch across, a foot, or even 100 feet? I do understand that a BEC entails overlapping de Broglie waves of the individual Bosonic entities. So presumably if one could attain matter wavelengths of the individual bosons of say a foot, that BEC's multiple feet across might be possible.