Abstract: Chemical reactions typically involve the dynamic reorganization of a large number of atoms and molecules. One persistent goal in the scientific community is to be able to visualize and manipulate individual molecules in a reaction and track their nuclear motions in real time. The combination of a femtosecond laser and a scanning tunneling microscope (STM) is believed to be the ultimate approach to achieve simultaneous spatial and temporal resolution. The coupling of femtosecond laser pulses to tunneling electrons breaks the diffraction limit in traditional optical microscopy and allows the detection of light-matter interactions with sub-Ångström resolution. The combination of the temporal resolution of the femtosecond laser and the spatial resolution of STM further enables the investigation of laser coherent dynamics of single molecule with joint femtosecond-Ångström sensitivity.