Autophagy is induced by an upstream signal such as starvation, the detection of pathogenic microorganisms in the cytosol or by damaged mitochondria. This signal triggers the most enigmatic and fascinating step of autophagy, the de novo formation of autophagosomes. Initially a small double membrane bound structure is formed, which grows and adopts the shape of a cup. This cup-shaped structure eventually fuses at its rims to form a double membrane bound organelle enclosing a part of the cell’s cytoplasm. The autophagosome then fuses with components of the classical endosomal system thereby maturing to an autolysosome within which the content is degraded. The degraded content can subsequently be used for the synthesis of factors that are essential for the survival of the cell.