A map from 1920 of southern Canada, the United States, and northern Mexico showing terrain features, lakes and river systems, and general vegetation types of the region. The map is keyed to show the submerged portion of the continental...

A map from 1916 of the United States showing the cities where the government maintained flood stations at the time. "Reservoirs to hold back flood waters have been proposed, but their construction would be very expensive. The Weather...

Described as "principal structure associated with the history of weather observation" in the United States, this observatory is home to the oldest continuous weather record in North America, and is where numerous meteorological...