Most of the matter and energy content of the Universe is thought to be in the form of dark matter and dark energy. Some of the largest international projects are driven by the need to understand properties of these dark components of the Universe. Strong gravitational lensing is a phenomenon where multiple images of a distant background galaxy can be seen due to light rays being deflected by a massive galaxy in the foreground. Gravitational lenses are rare but have a wide range of applications. These include studying the distribution of dark matter and its evolution over time in galaxies and galaxy clusters, the dark matter fraction, understanding how dark energy affects growth of structure and its evolution over time. In my talk, I will present my ongoing projects which use strong lensing to address these questions.