 We are pleased to present you a short video outline of our review visualizing cellulose activity to be published in biotechnology and bioengineering. The authors of this review are Dr. Patricia Bubner from the Institute of Biotechnology and Biochemical Engineering at Graz University of Technology, Austria, Dr. Harald Plank from the Institute for Electron Microscopy at Graz University of Technology, Austria, and Professor Dr. Bernd Niedetzky from the Institute of Biotechnology and Biochemical Engineering at Graz University of Technology, Austria. In order to exploit the abundant lignocellulosic biomass available, efficient enzymatic conversion of cellulose is key. Rational design of the process, however, is dependent on thorough comprehension of enzymatic disruption of cellulose. Several fungi and bacteria express efficient enzyme systems called cellulases to degrade cellulose. However, despite decades of research, our comprehension of enzymatic cellulose degradation is still not well advanced. This is reflected in our current simplistic model of enzymatic cellulose degradation, which has not changed much in the last 30 years. While the molecular mechanisms of cellulases are well understood, we lack meso- and nanoscale evidence of the processes happening directly on the surface of the insoluble substrate. This information is not accessible using biochemical methods. However, it can be imaged using biophysical methods. Visualization of cellulases, their structural dynamics and implications on the cellulose surface, has well advanced our knowledge about the process. Our review addresses the approaches taken in order to understand enzymatic lignocellulose degradation using advanced imaging techniques. We discuss first the methods employed for visualization, second the substrates used and third the milestones achieved in studies in the past 32 years. The methods used for visualization are optical microscopy, electron microscopy and atomic force microscopy. Among optical microscopy methods, modern fluorescence microscopy has been successfully used in visualization of labelled cellulases and or substrates. The CFM principle is outlined schematically here. This is an example from a recent publication showing a typical confocal image of cellulose microfibrils with bound CBH1. Electron microscopy. In transmission electron microscopy, high resolutions down to the atomic scale can be achieved. It was widely used in the beginning of cellulase visualization in the 80s. However, due to the non-environmental conditions used, TAM application for cellulase visualization is limited. Classical scanning electron microscopy needs an electrically conductive surface layer and vacuum in the sample chamber. Environmental SEM allows measurements at higher pressures and is thus suitable for investigation of hydrated and uncoded biological samples. Atomic force microscopy. In AFM, a sharp tip which is mounted at the end of a flexible cantilever is rastered over the sample surface, thus allowing to access surface structural dynamics. In a so-called liquid cell, samples can be imaged in environmental conditions at ambient temperature and pressure in liquid. In the last decade, several AFM studies gave impressive insight in behavior of cellulases and the structural dynamics of enzymatic cellulose degradation. The various cellulose substrates used in the studies reviewed are bacterial and algal cellulose, plant cellulose and various cellulose model substrates. Finally, we show here some of the milestones in cellulase visualization which are discussed in our review, such as the first TAM study on this matter by White and Brown in 1981, the visualization of CBH1 processivity using high-speed AFM in 2011, the empirical model of cellulose surface structural dynamics during enzymatic degradation published in 2012 and the in-situ visualization of the mesoscopic structural dynamics of cellulases using AFM. Here you see the three-dimensional superimposition of AFM images, depicting the degradation of a mixed amorphous crystalline cellulose by a complete cellulase system of trichoderma resi. If we zoom in, we can observe the structural dynamics happening during degradation directly on the surface. In slow motion, the degradation of single fibrils can be clearly seen. This was a video highlight on the review visualizing cellulase activity by Patricia Bubner, Harald Plank and Bernd Niedetzky. We want to thank Manuel Eibinger and Thomas Ganna for helping preparation of this video.