For no particular reason other than it is a really nice image, here’s a picture from the Sheffield Polymer Physics Group. It’s an AFM image of a thin film of a block copolymer – a molecule with a long section that can crystallise (poly ethylene oxide), attached to a shorter length of a non-crystallisable material (poly vinyl pyridine). What you can see is a crystal growing from a screw dislocation. The steps have a thickness of a single molecule folded up a few times.
Image width 20 microns. Image by Dr Cvetelin Vaslilev, image post-treatment by Andy Eccleston.