townhouse

AG is likely Alfred Gwynne Vanderbilt. The "Mrs" is unclear to me. He divorced his first wife ca. 1909, and remarried 1911. He died on the Lusitania.

The widow was born Margaret Emerson, herself an heiress of the Bromo Seltzer fortune:

"[Isaac Edward] Emerson's daughter Margaret married at 18 to Dr. Smith Hollins McKim. They became social leaders in New York's high society. But in 1910 she brought a sensational divorce suit against her husband, claiming he beat her in drunken rages. She remarried in 1911, this time to Alfred Gwynne Vanderbilt I, one of the wealthiest men in America having inherited the bulk of his father's fortune in 1889. They had two sons, Alfred Gwynne Jr. and George. Tragically, while traveling to England on business, Alfred Sr. heroically lost his life in the sinking of RMS Lusitania by torpedo in 1915. Margaret inherited her husband's fortune (as well as the bulk of her father's fortune when he died). One son from this marriage, Alfred Gwynne Vanderbilt II went on to become one of the driving forces behind thoroughbred racing in America. Margaret married two more times, both ending in divorce. In 1931 she legally resumed her maiden name."
en.wikipedia.org/wiki/Captain_Isaac_Edward_Emerson
Margaret Emerson's obituary from January, 1960:
select.nytimes.com/gst/abstract.html?res=9D06E4DD1138E333...

A.G. Vanderbilt in another Bain photo:

hdl.loc.gov/loc.pnp/ggbain.05295 is a picture of Mrs. Mckim/Vanderbilt from the Bain collection -- not yet uploaded to Flickr.

I haven't been able to identify this building. Sources I have consulted say she was living at the Vanderbilt Hotel at the time the Lusitania sank.

And I've found two houses she owned at some point but which it isn't: The Gould house on Fifth Avenue and Eat 67th shown in www.oldpokerchips.com/NonNevada/Gould.htm And a grand house in London, which he left her in his will according to NYT of May 30, 1915 query.nytimes.com/gst/abstract.html?res=F50B17F9385C13738... Gloucester House at Piccadilly and Park Lane pictured at www.amsprop.com/gloucester_house/index.html

More discussion of the N street/Union street issue here: elizatruitt.wordpress.com/2007/03/27/anacostia-market/

Title: The House of Two-faces'

looks like a storm was coming. Or someone was burning garbage? :0)

Is there a corner of N and Union Street in DC?

The corner in question is now the West end of N St. SW , at roughly 38.874676,-77.018784 (found using Google Maps). What used to be Union St. ran perpendicular to that point between M and O Streets. From the satellite images, it doesn't look like any of the buildings remain. Anyone know what that new development is?

Here's the present day satellite photo.

The area is currently occupied by condos and apartment buildings, none of which are architecturally noteworthy or distinguished. Arena Stage is also located in the general vicinty. Southwest Washington was once alive with people and streetlife. The urban "renewal" of the 1950s and 60s turned the area into a clean but sterile urban wasteland.