The Gowanus Canal is a Brooklyn waterway that, during the Industrial Revolution in the mid-19th century and beyond, served as a receptacle of waste for the various companies that fueled the way.
Specifically, the canal served as a dumping ground for coal tar, a thick, black liquid containing benzene, naphthalene, phenols, aniline and a bunch of other hazardous chemical compounds. After it was no longer needed, the canal was left to fester, and the tar substance seeped underground, floated to the surface, and interspersed itself throughout the fetid body of water, yielding a virulent stench and strangely stunning visuals.