An enormous amount of four dimensional effective field theories can be obtained from compactifications of string theory, forming a set known as the landscape of string theory. It has been suggested that, beyond this landscape, there exist consistent-looking effective field theories that cannot be embedded into UV complete theories of quantum gravity, in particular into string theory. They are said to belong to the swampland. In this talk, I will describe some of the conjectures that define the swampland and implications they have on phenomenology (e.g. dark matter, inflation and the cosmological constant).