|Not part of Riordanverse|
Washington Square Park is a public park in Manhattan.
Sikander Aziz and Daoud cut through the park on their way to Manhattan General Hospital. They find park workers cutting down sick trees and flowers covered in sludge. Sik deduces that Nergal was behind the sick plants. A few weeks later, Sik sees it from the air as he is flying to the hospital with a cure for Nergal's plague.