The goal of my project is to develop experimental proposals aiming to collect evidence that quantum effects, such as quantum superposition and entanglement hold at large scales. This includes proposals for light-atom interfaces to demonstrate that entanglement can survive over hundreds of kilometers through quantum networks, photonic experiments aiming to bring quantum effects to the domain where they can be observed by the human eyes, light-mechanical interfaces to demonstrate that entanglement applies to massive macroscopic systems. Behind their fundamental interest to gain insight into the reasons that makes it hard to observe quantum effects at macroscopic scales, our research have important applications for long distance quantum communications and quantum metrology.