This 1895 map of New York City was created by socialist activist Walter Vrooman, who hoped that by showing the "concrete socialism" of every street, park, school, public building, and public dock in red (and allowing private enterprises to recede into the white background), he might persuade readers that the rest of the map should be socialist as well.
From the Norman B. Leventhal Map Center/Boston Public Library
Ken Liu’s speculative fiction on maintaining and transcending humanity
The clouds that make up the Radcliffe Wave (highlighted in red) pass within just 500 light years of our sun (yellow). Wave data has been superimposed on an artist’s rendering of the Milky Way galaxy as it appears in a screen shot taken from WorldWide Telescope.
Image courtesy of Alyssa Goodman, Harvard University