The spatial and temporal organization of the cell nucleus and its components is essential for genome regulation. The nuclear envelope maintains the shape and the mechanical integrity of the nucleus, but also provides an anchor for chromatin that is connected to its inner side. This interaction mediates the regulation of gene expression, DNA replication and the maintenance of genome stability. Cell nuclei need to be rebuilt after each cell division, and this is achieved in a remarkable short period of time. My lab use state-of-the art microscopy (live and super-resolution), as well as complementary approaches, to understand how human telomeres, natural ends of linear chromosomes, play an essential role in this critical process.