Seamless stitching of graphene domains on polished copper (111) is proved clearly not only at atomic scale by scanning tunnelling microscopy (STM) and transmission electron micoscopy (TEM), but also at the macroscale by optical microscopy after UV-treatment. Using this concept of seamless stitching, synthesis of 6 cm x 3 cm monocrystalline graphene without grain boundaries on polished copper (111) foil is possible, which is only limited by the chamber size.