A comprehensive understanding of rock salt rheology is required for constraining laboratory derived constitutive laws that predict the long-term behavior of salt engineering structures. To reduce risks in the operation of radioactive waste repositories and solution mined salt caverns for gas- and energy storage, the processes defining salt flow in nature need to be assessed. Based on case studies (Netherlands, Israel and Romania) from various salt tectonic settings the influence of grain-size, impurity content, mechanical stratigraphy and tectono-stratigraphic inhomogeneities to salt rheology in nature is investigated. Analysis of relatively undeformed, diapiric, or detachment salt integrates seismic, microstructural and numerical analysis with digital outcrop models and further field observations. This study builds on optical microscopy of gamma-irradiated thin sections (OM-GTS ), grain- and subgrainsize piezometry, and seismic analysis and presents an integrated approach of OM-GTS to compliment further methods (electron backscatter diffraction (EBSD), x-ray diffraction analysis (XRD), scattered electron microscopy with energy dispersive x-ray analysis (SEM-EDX), magnetic properties analysis, drone-based digital outcrop models, field work, finite-element MILAMIN, MUTILS and FOLDER codes, discrete-element (DEM) ESyS particle codes).A seismic study of the Z2 Zechstein salt from the Friesland platform in the Northern Netherlands, which was not affected by later major tectonic movement, indicates that Zechstein salt deposition was syn-tectonic. Anhydrite-carbonate Z3 stringer rupturing and local deposition of Z3 salt filled depressions above active basement faults is interpreted to have major effects on the evolution of the internal structure and formation of salt pillows and diapirs. Drill-core rock salt Z2 Kristalllagen (Stassfurt Formation) samples from the same area are compared to the diapiric equivalent Kristallbrocken from Winschoten, Zuidwending and Pieterburen in the Northern Netherlands. Microstructural ...