This was taken on a Transmission Electron Microscope (TEM) which is conceptually similar to a normal microscope except that it uses electrons rather than light (photons). Electron wavelengths can be much smaller than light wavelengths so it produces a greater magnification.
The centre dot is the e-beam, the larger brighter dots are images of the individual columns of Manganese atoms and the smaller fainter dots are the silicon. The scale is in micrometres, which is bafflingly small and hard to visualise in our human scale!
The image was taken by Matt LeBlanc, a very interesting physicist studying at Acadia University and soon to be working at Cern. It is one of the most beautiful things ever given to me. I could stare endlessly at it pondering other dimensions of scale and time.