As water begins to form ice on a cold surface, it first lays down a frozen layer of single atoms.
The picture shows ice one atom thick on a very cold surface.
This is the very first stage of freezing, followed by a thickening formation of layers of ice crystals.
Sandia Labs snapped the first photos of nanometer-thick ice films taken by a scanning tunneling microscope to capture how water molecules deposited an ice film.
From Scientific American, phenomenal pics department.