The unsteady wake behind a circular cylinder was experimentally studied and compared with numerical results. The location and evolution of coherent structures, or vortices, in the flow were analyzed to facilitate the understanding of the complex vortex shedding physics in the near wake region. This understanding is critical to the control of vortex shedding from bluff bodies. The two-dimensional velocity data was collected using a 2D DPIV measurement system. The data was phase-averaged using snapshot Proper Orthogonal Decomposition (POD) and pressure measurements from the cylinder surface. The Eulerian Q-criterion was applied along with a Lagrangian coherent structures (LCS) analysis to numerical and experimental data to determine the properties of the wake.