Primary cilia are microtubule-based projections found on the surface of nearly every cell in our body. In the last two decades it has become clear that primary cilia have evolved to be key regulatory hubs of the cells, as they concentrate or segregate components of major cellular signalling pathways. Dysfunctional cilia can lead to nearly 40 severe human genetic syndromes (ciliopathies) with highly heterogeneous, overlapping phenotypes, affecting as many as 1 in 400 people. We now know that humans critically depend on cilia to see, hear, smell, breathe, excrete and reproduce. Such activities require a high degree of regulation and critical feedback to ensure robustness in development and homeostasis of different cells, tissues and organs.