Abstract: Dy2Ti2O7 is a material with a pyrochlore lattice of corner-sharing tetrahedral. Crystal-field effects constrain the magnetic moments of the rare-earth ions to point along the axis connecting the centres of the two neighbouring tetrahedra. As a result, the magnetic moments are highly frustrated and possess a ground state containing a large residual entropy similar to water ice. Because of this similarity to water ice, the system is called a spin ice. Recently a very interesting perspective has been developed in which the thermal excitations in the magnetic spins are viewed as magnetic monopoles. In this talk, I will review some of the progress in understanding spin ice and the monopole picture. I will discuss my group's results of specific heat, ac susceptibility and magnetization measurements.