In Math 731, we studied Berkovich analytic spaces, which are analogues of complex analytic spaces over non-archimedean fields. In this talk, we will explore other approaches to non-archimedean geometry. Tate was the first to successfully develop a form of non-archimedean geometry. Here, the basic objects of study are rigid analytic spaces. These are obtained by gluing maximal spectra of affinoid algebras endowed with Grothendieck topologies. However, rigid spaces are deficient in points, so several refinements have evolved. Raynaud treats rigid spaces as generic fibers of formal models over the valuation ring. Huber develops a new framework called adic spaces, which are generalizations of rigid spaces. If time permits, we will also discuss cohomology of these spaces.