Dear Colleagues, We invite you to register for our conference "6th Conference of the Polish Society on Relativity" – POTOR-6 which will take place in Szczecin, Poland from 23rd to 26th September 2019. The abstract submission deadline is June 30 th, 2019. The registration deadline is 31 st July 2019. Full information is available on our webpage: https://indico.cern.ch/event/773241/overview Conference email is: potor6@gmail.com The 6th Conference of the of the Polish Society on Relativity is organised by the Szczecin Cosmology Group on behalf of Polish Society on Relativity. The conference is the regular annual meeting of the Society which is open to international invited speakers and participants. The conference covers all aspects of classical relativity as well as related fields including contemporary theories of unification and quantum gravity. Topics include: Theoretical and numerical relativity. Black holes: classical and quantum aspects. Relativistic cosmology. Early universe, dark matter, and dark energy problems. Gravitational waves. Approaches to quantum gravity. Quantum cosmology. Relation of relativity and superstring theory. Invited speakers are: Joseph Conlon (Oxford), Salvatore Capozziello (Napoli), Jacques Delabrouille (Paris), Jose Anthony Font (Valencia), Hermann Nicolai (AEI, Golm), Edward Porter (APC, Paris, France), Jorge Pullin (Lousiana State Univ., USA), Masaru Shibata (Yukawa Institute, Kyoto, Japan), Massimo Tinto (Univ. San Diego, USA). We are looking forward to seeing you in Szczecin. Yours faithfully, Adam Balcerzak (Organizing Committee chair) Mariusz P. Dąbrowski (Scientific Committee chair)