I found more information about why they used the title "Street of Nations" on these series. The term references a standard feature of World's Fairs of the time that was first introduced in 1878:
"The exhibits and their arrangement at the 1878 Exposition Universelle were not just modifications of the earlier fair, however. Perhaps the most innovative and most widely admired feature of the fair was the Street of Nations. In the central courtyard of the Palace of Industry, each participating nation was invited to build an entranceway to its exhibits. The result was a splendid row of facades that announced, in architectural terms, the character and aesthetic values of every nation. The Street of Nations not only gave the visitors a prelude to the exhibits within the Palace. The whole ensemble taken together allowed fairgoers to see, at one glance, the eclectic nature of the world in 1878."
The quote was taken from this webpage:
Paris 1878 Exposition: History, Images, Interpretation — Ideas