Throughout human history, defensive walls were frequently built around cities, making them impenetrable by enemies. A different kind of wall, the plant cell wall, represents the first protective barrier against invasive pathogens. The plant cell wall is mainly composed of cellulose, pectin, and hemicellulose. To penetrate the plant cell wall, plant pathogens secrete cell-wall-degrading enzymes that can disrupt these three major components. In their new Spotlight comment titled "A war on the cell wall", Zhengquin Fu and his collaborators highlight and discuss a recent study from Sabbadin et al. published in Science that revealed novel functions of copper-bound lytic polysaccharide monooxygenases from the potato late blight pathogen Phytophthora infestans in plant-cell-wall penetration. A fascinating read!