around the new theatres. The new system also needed an organized way to engage actors for these one-off productions, so talent brokers and theatrical agents sprang up, as did theatrical boardinghouses, stage photographers, publicity agencies, theatrical printers and play publishers. Along with the hotels and restaurants which serviced the theatregoers and shoppers of the area, the Union Square Rialto was, by the end of the century, a thriving theatrical neighborhood, which would soon nonetheless migrate uptown to what became known as "Broadway" as the Rialto became subsumed into the more vice-oriented Tenderloin entertainment district. Office and wholesale district By the first decade of the 20th century, Union Square had grown into a major transportation hub with several elevated and surface railroad lines running nearby, and the New York City Subway's 14th Street–Union Square station having opened in 1904. With the northward relocation of the theater district, Union Square also became a major wholesaling district with several loft buildings, as well as numerous office buildings. The office structures included the Everett Building, erected at the northwest corner of Park Avenue South and 17th Street in 1908; the Germania Life Insurance Company Building, erected at the northeast corner of the same intersection in 1910–1911; and the Consolidated Edison Building, constructed three blocks south at 14th Street between 1910 and 1914. During this era, many of the older homes on Union Square were converted into tenements for immigrants and industrial workers. Numerous artists relocated into the attics of the remaining mansions along 14th Street, where they had their studios. The 1939 WPA Guide to New York City said that by the 1920s, "south side of Fourteenth Street became virtually an ex-tension of Greenwich Village." Further, real estate values around Union Square had declined by the 1920s, with "burlesque houses, shooting galleries, and shoddy businesses" lining the square. Throughout the decade, most buildings on the eastern part of the square were purchased by department stores S. Klein and Ohrbach's. Real estate activity resumed in the late 1920s, and according to a 1928 piece in The New York Times, “several smaller operations are planned or are under way in the neighborhood". Late 20th and early 21st centuries Union Square was named a National Historic Landmark in 1997, primarily to honor it as the site of the first Labor Day parade. Following the September 11 attacks in 2001, Union Square became a primary public gathering point