In recent years, more and more gravitational wave events have been recorded from the ground based detectors. This, has led to the publication of the first catalogues of Gravitational Wave sources, which have contributed to the improvement of our understanding of the nature of such cataclysmic events. Now, the community is developing new detectors, with improved sensitivity, focusing on different parts of the Gravitational Wave spectrum. One of them, is the ESA Laser Interferometer Space Antenna (LISA), a space born Gravitational-Wave observatory scheduled to be launched in the early 2030s. In this talk I will present an overview of the mission and its main scientific goals. I will also highlight the implications to astrophysics and cosmology, as well as the various technical challenges that we will have to face operating a space-borne detector such as LISA.