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Spatio-temporal patterns in catalytic CO oxidation have been studied on a facetted Pt(1 1 0) surface in the 10 −5 mbar range using low energy electron microscopy (LEEM). Prior to the LEEM experiments the surface had been facetted by exposing the sample to reaction conditions in the 10 −4 mbar range. Irregularly shaped spiral waves, interacting oxygen fronts, travelling CO islands with slowly decaying trails and travelling wave fragments exhibiting a superimposed slow rotation have been found. The experimental results are discussed in terms of reversible facetting changing the anisotropy of the surface and adding a slow time scale to the dynamics of the reaction.