Day 223 of #LMB365 shows Aaron Klug beside an electron microscope at the LMB. Aaron was born #OTD in 1926. He was instrumental in revealing the structures of complex biological molecules, from viruses to tRNA, to chromatin and zinc fingers. His most important contribution to scientific research was his painstaking development of crystallographic electron microscopy. This combines the techniques of electron microscopy and X-ray diffraction to recover three-dimensional structural information from two-dimensional electron micrographs. For this he was the sole recipient of the 1982 @Nobel Prize in Chemistry