  Knowledge of the molecular structure is key to understanding the function of
participating molecules in photo-induced chemical reactions. Visualizing the
nuclear dynamics of a photochemical reaction requires an ultrafast measurement
technique that can identify the location of atoms in molecules with atomic
{\AA}ngstrom spatial resolution evolving on the nuclear (i.e. hundreds of
femtosecond) timescale. Coulomb explosion imaging (CEI) and laser-induced
electron diffraction (LIED) offer the required sub-{\AA}ngstrom spatial and
tens of femtosecond temporal resolution to track in real-time changes in the
molecular structure. In this tutorial review, details of the tools, analysis
procedures, exemplary previous results and future perspectives of both CEI and
LIED techniques are described.
