The authors report the successful preparation and study of free-standing two-dimensional (2D) atomic crystals, which are individual atomic planes extracted from bulk crystals or unrolled single-wall nanotubes. Using micromechanical cleavage, they prepared and characterized a variety of 2D crystals, including boron nitride, graphite, dichalcogenides, and complex oxides. These atomically thin sheets are stable under ambient conditions, exhibit high crystal quality, and maintain macroscopic continuity. The dimensionality of materials significantly influences their properties, and while quasi-0D, quasi-1D, and 3D structures are well-studied, 2D crystals have been less explored. The authors developed a cleavage technique that allows the isolation and study of individual crystal planes from strongly layered materials. They identified 2D crystallites through optical microscopy and confirmed their monocrystalline nature using atomic force microscopy (AFM). The 2D materials were further investigated using scanning tunneling microscopy (STM), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM). Electrical conductivity measurements revealed that 2D materials like graphene and dichalcogenides exhibit metallic behavior with pronounced electric field effects, while others like BN and MoS2 are highly insulating. The findings highlight the potential of 2D crystals for new materials applications and the possibility of growing them in large sizes for industrial use.The authors report the successful preparation and study of free-standing two-dimensional (2D) atomic crystals, which are individual atomic planes extracted from bulk crystals or unrolled single-wall nanotubes. Using micromechanical cleavage, they prepared and characterized a variety of 2D crystals, including boron nitride, graphite, dichalcogenides, and complex oxides. These atomically thin sheets are stable under ambient conditions, exhibit high crystal quality, and maintain macroscopic continuity. The dimensionality of materials significantly influences their properties, and while quasi-0D, quasi-1D, and 3D structures are well-studied, 2D crystals have been less explored. The authors developed a cleavage technique that allows the isolation and study of individual crystal planes from strongly layered materials. They identified 2D crystallites through optical microscopy and confirmed their monocrystalline nature using atomic force microscopy (AFM). The 2D materials were further investigated using scanning tunneling microscopy (STM), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM). Electrical conductivity measurements revealed that 2D materials like graphene and dichalcogenides exhibit metallic behavior with pronounced electric field effects, while others like BN and MoS2 are highly insulating. The findings highlight the potential of 2D crystals for new materials applications and the possibility of growing them in large sizes for industrial use.