The paper reports the observation of Majorana fermions in ferromagnetic atomic chains on a superconductor. The authors fabricated ferromagnetic iron (Fe) atomic chains on the surface of superconducting lead (Pb) and used high-resolution spectroscopic imaging techniques to study the electronic properties of these chains. They found that the onset of superconductivity in the Fe chains, which gaps the electronic density of states in the bulk, is accompanied by the appearance of zero-energy end states. This spatially resolved signature provides strong evidence for the formation of a topological phase and edge-bound Majorana fermions in the atomic chains. The study demonstrates a method for fabricating one-dimensional topological superconductors and detecting their Majorana fermions, achieving both spatial and spectral resolution. The results are consistent with theoretical models and provide a platform for future experiments to manipulate Majorana fermions and realize other related topological superconducting phases.The paper reports the observation of Majorana fermions in ferromagnetic atomic chains on a superconductor. The authors fabricated ferromagnetic iron (Fe) atomic chains on the surface of superconducting lead (Pb) and used high-resolution spectroscopic imaging techniques to study the electronic properties of these chains. They found that the onset of superconductivity in the Fe chains, which gaps the electronic density of states in the bulk, is accompanied by the appearance of zero-energy end states. This spatially resolved signature provides strong evidence for the formation of a topological phase and edge-bound Majorana fermions in the atomic chains. The study demonstrates a method for fabricating one-dimensional topological superconductors and detecting their Majorana fermions, achieving both spatial and spectral resolution. The results are consistent with theoretical models and provide a platform for future experiments to manipulate Majorana fermions and realize other related topological superconducting phases.