Abstract: The current expansion rate of the Universe is captured by the so-called Hubble constant, which is a key parameter in the, extremely successful, standard model of cosmology. As such, The Hubble constant can be measured in several different ways: looking at the light of the “early Universe”, looking at bright objects in the “late Universe” (an approach close to Hubble original approach) and other in-between options. These are like readings of different speedometers, each measuring the speed of expansion of the Universe in its peculiar way. Each of these measurements is very precise: error-bars are at the percent level. However, their values do not seem to agree too well. These are exquisitely sophisticated, and challenging measurements. Yet one may ask: can this be a signature that the cosmological model starts showing some cracks and that we might need to invoke new physics? I will introduce this modern-day cosmic puzzle, discuss its implications, what this tension has taught us so far and possible future prospects.