Parker Dam was constructed on the California-Arizona border on the lower Colorado River during the 1930s, as part of a project to employ people during the Great Depression, to generate electricity, and to provide water that could be pumped into aqueducts for agricultural, industrial, and residential use in other parts of Arizona.

The sandy peninsula of Cape Cod, Massachusetts juts into the Atlantic Ocean with its characteristic crook and twirl in both images: “Balloon View–Nantucket to Boston” made in 1885, and a Landsat 8 satellite image made 129 years later in 2014. Aspirations to rise above the Earth and to record the Earth’s surface from there are a long-standing theme of human culture.