Bacterial cell wall peptidoglycan is essential for the life of most bacteria. It determines cell shape, and its biosynthesis is the target for many important antibiotics. The fundamental chemical building blocks of peptidoglycan are conserved: repeating disaccharides cross-linked by peptides. However, despite this relatively simple chemistry, how this is manifested into the myriad bacterial shapes and how this single macromolecule remains dynamic permitting cell growth and division has largely remained elusive. The advent of new microscopy approaches is beginning to revolutionize our understanding of the architecture of this polymer and to reveal novel insights into its biosynthesis and hydrolysis. Atomic force microscopy has demonstrated a complex, nanoscale peptidoglycan architecture in diverse species, which meets the challenges of maintaining viability and growth within their environmental niches by exploiting the bioengineering versatility of the polymer. The application of super-resolution fluorescence microscopy, coupled with new chemical probes has begun to reveal how this essential polymer is synthesized during growth and division.