The intergalactic medium (IGM) in large-scale filaments plays an important role in the formation and evolution of galaxies. My interest lies in studying the properties of the IGM gas and how it affects the galaxies within them, as well as the connection of the large-scale structure to the underlying cosmology. Through simulations I make predictions for observations of the IGM targeting emission lines of neutral hydrogen in emission (i.e. 21 cm in the radio) or in absorption through Lyman alpha tomography.