The National September 11 Memorial and Museum at the World Trade Center, which holds artifacts such as the last column standing from the towers, is now flooded with at least five feet of water. This, and other items like the famous cross-shaped steel beam and one of the tower's stairways, were located on the museum's main floor, which is roughly 68 feet below the memorial plaza.
According to the New York Times, the museum was built on a 100-year flood plain, land that has a 1 percent chance of flooding annually. However, the site has experienced two 100 year floods since last August after Hurricane Irene and now Hurricane Sandy. At the moment, authorities are still unclear of the extent of the damage.