We present an overview of the advances made during the past 15 years by the Atomic Physics and Astrophysics Group of Mons University regarding the analysis of the spectra, the transition probabilities, and the radiative lifetimes in heavy elements. More precisely, this review is focused on neutral and lowly ionized atoms belonging to the lanthanide group, the fifth row, and the sixth row of the periodic table (Z = 37–86), for which a very large amount of new data has been obtained.