Subject: Is there an upper limit in terms wavelength to the electromagnetic spectrum

I never got a clear answer from my physics teacher on this one. 
Physics texbook always show the electromagnetic spectum going from 
short wavelength (cosmic rays, X-Rays..) to longer wavelengths (radio 
waves). I understand there is no sense in asking what`s the limit in 
very short wavelengths, since the corpuscular nature of em will 
manifest itself. But what about the other end ? In other words, is it 
possible to have a wavelength of 100m, 100000 km, or even the size of 
the universe ?

Re: Is there an upper limit in terms wavelength to the electromagnetic spectrum