Flat slabs supported on columns are one of the most commonly used structural systems for buildings. There is a need for a greater and deeper knowledge of their behaviour as a part of the whole system of the building. The SlabSTRESS project was set up to test a real scale flat slab building under seismic and cyclic loading at the Reaction Wall of the European Laboratory for Structural Assessment of the Joint Research Centre in Ispra (Italy). Owing to the unique dimensions and testing capabilities of the ELSA Reaction Wall, the SlabSTRESS test campaign could not be performed elsewhere in Europe. The experimental campaign was part of the Transnational Access activities of the SERA (Seismology and Earthquake Engineering Research Infrastructure Alliance for Europe) project, which received funding from the European Union's Horizon 2020 Research and Innovation programme. The SlabSTRESS user team was made up of a group of European institutions, led by the Politecnico di Milano together with EPFL Lausanne, UNOVA Lisbon and UTCB Bucharest. The project provided new knowledge on the response of flat-slab structures and column-slab sub-assemblies. The results will help calibrate models, and verify the rules in European and international standards, namely the Eurocodes and Model Code. It will contribute to the development of new rules for the design and detailing of flat-slab structures subjected to earthquake and gravity loads, and ultimately improve their safety.