Quantum mechanics and general relativity are two fundamentally different theories and have both been tested independently with very high precision. However, even after a century of research, the interplay of those two very different theories has never been tested experimentally. Within this talk I will present the experimental research aiming to explore this interface between quantum mechanics and general relativity by performing high-precision experiments at the level of single quanta of light, the photons. Such quantum systems allow one to examine the influence of gravity on interference effects. For this purpose, a high-precision interferometer whose paths are subject to different gravitational potentials will be used.