Photo: Swamps of Washington DC
The Washington DC area was originally quite swampy with marshes and wetland areas. The city used dirt and cotton bales as a foundational fill to cover swamp areas and to allow for what is today an asphalt, glass and steel metropolis. This photo of a marshy stretch along Roosevelt Island, which lie in the Potomac directly across from the city, gives an idea of what the pre-capitol landscape may have looked like.