NEW YORK SUBWAY ART

I really like those signs in the New York Subway and how those mosaic letters show us the way underground, but what is the story behind it:

The first “signs” in the New York City subway system were created by Heins & LaFarge, architects of the IRT(Interborough Rapid Transit). In 1904 they established the now-familiar tradition of mosaic station names on platform walls. The name tablets were composed of small tiles in both serif and sans serif roman capitals. The BRT (Brooklyn Rapid Transit)/BMT (Brooklyn-Manhattan Transit) followed suit under Squire J. Vickers, who took over the architectural duties in 1908. Neither line had a uniform lettering style even though the designs were prepared in studio and then shipped in sections to the stations. Thus, there is a surprising amount of variety within the mosaic station names. Smaller directional signs—with arrows indicating exits from each station—were also made in mosaic tile in both serif and sans serif roman capitals. Vickers simplified the decorative borders surrounding the name tablets but did not alter the lettering styles of either the IRT or the BMT. However, when the IND  (Independent) was established in 1925, he created a new style of sans serif capitals to accompany the stripped-down decoration of the stations. These letters, inspired by Art Deco, were heavier and more geometric than the earlier sans serifs rooted in 19th-century grotesques. They used larger tiles than the IRT and BMT mosaics, though the IND's directional mosaic signs employed lighter sans serif capitals and were made up of smaller tiles. (text via Aiga)