Structural DNA nanotechnology, developed over the past 30 years, uses synthetic branched DNA and sticky-ended cohesion to create novel DNA-based materials. This approach enables the construction of polyhedra with DNA double helices as edges and vertices at branch points, and the formation of two- and three-dimensional periodic DNA lattices (crystals). DNA has also been used to create nanomechanical devices, such as shape-changing molecules and DNA walkers. These devices are integrated into DNA arrangements, with sequence-dependent functions driven by nucleotide pairing. The field relies on three pillars: hybridization, stably branched DNA, and convenient synthesis of designed sequences. Hybridization allows the self-assembly of DNA structures, while stably branched DNA forms robust motifs. Convenient synthesis enables the creation of arbitrary DNA sequences. Sticky-ended cohesion is crucial for precise DNA structure formation, as it allows predictable and programmable interactions. DNA nanotechnology has led to the creation of various structures, including 2D and 3D crystals, DNA origami, and nanomechanical devices. DNA origami, for example, uses a long DNA strand as a scaffold to fold into specific shapes. 3D crystals, such as tensegrity triangles, have been crystallized with high resolution, enabling detailed structural analysis. DNA-based nanomaterials have also been used to organize other molecular species, such as nanoparticles, and to build nanoelectronic and nanophotonic components. The field has grown rapidly, with many laboratories now involved in DNA nanotechnology. Advances include algorithmic assembly, which allows the creation of complex patterns using simple tiles, and the development of autonomous nanomechanical devices. The future of DNA nanotechnology is promising, with potential applications in medicine, materials science, and nanotechnology. The field continues to evolve, with ongoing research into new materials, improved devices, and the integration of DNA with other molecular species.Structural DNA nanotechnology, developed over the past 30 years, uses synthetic branched DNA and sticky-ended cohesion to create novel DNA-based materials. This approach enables the construction of polyhedra with DNA double helices as edges and vertices at branch points, and the formation of two- and three-dimensional periodic DNA lattices (crystals). DNA has also been used to create nanomechanical devices, such as shape-changing molecules and DNA walkers. These devices are integrated into DNA arrangements, with sequence-dependent functions driven by nucleotide pairing. The field relies on three pillars: hybridization, stably branched DNA, and convenient synthesis of designed sequences. Hybridization allows the self-assembly of DNA structures, while stably branched DNA forms robust motifs. Convenient synthesis enables the creation of arbitrary DNA sequences. Sticky-ended cohesion is crucial for precise DNA structure formation, as it allows predictable and programmable interactions. DNA nanotechnology has led to the creation of various structures, including 2D and 3D crystals, DNA origami, and nanomechanical devices. DNA origami, for example, uses a long DNA strand as a scaffold to fold into specific shapes. 3D crystals, such as tensegrity triangles, have been crystallized with high resolution, enabling detailed structural analysis. DNA-based nanomaterials have also been used to organize other molecular species, such as nanoparticles, and to build nanoelectronic and nanophotonic components. The field has grown rapidly, with many laboratories now involved in DNA nanotechnology. Advances include algorithmic assembly, which allows the creation of complex patterns using simple tiles, and the development of autonomous nanomechanical devices. The future of DNA nanotechnology is promising, with potential applications in medicine, materials science, and nanotechnology. The field continues to evolve, with ongoing research into new materials, improved devices, and the integration of DNA with other molecular species.