Two clear and long-known features of the spectrum of extragalactic cosmic rays are the 'ankle', which is a flattening of the spectrum at around 5 x 10 eV, and suppression of the cosmic ray flux at high energies (above about 4 x 10 eV). More recently the Pierre Auger Observatory also observed a steepening of the cosmic ray spectrum above the ankle, before the steep cutoff above than 10 eV (see figure). The spectrum measured by the Pierre Auger Observatory does not appear to depend on the arrival direction of the cosmic rays. However, there are some discrepancies between the spectrum (specifically the energy at which the suppression of flux occurs) measured by the Pierre Auger Observatory in the Southern hemisphere and the Telescope Array in the Northern hemisphere. It is unclear whether this is the result of an unknown systematic error or a true difference between the cosmic rays arriving at the Northern and Southern hemispheres.