Hey lady, if you move, people in 123 years won't be able to clearly see your face.

I suspect that the basement was the former home of the Keystone Laundry -- the sign for which is mounted on the railing at the entrance to the stairwell. I say former because there's a really tiny sign above the one for the 20th Century Cigar that reads "This Basement for Rent".

[If the laundry is gone, wouldn't the sign be too? - Dave]

Today this site is occupied by the Martin Luther King Memorial Library, headquarters of the DC Public Library. This 1972 masterpiece is the only building in DC designed by Ludwig Mies van der Rohe.

You can see the stairs going down at the left of the long railing.
That leaves a long distance after going down one flight of stairs.
I wonder what was in the shoppes down there?

Every brand of cigar that O. H. Hoover carries appears to be priced at 5 cents. I calculate that to be about $18 today. Five cents was probably the bait price. Once inside, you'd be steered to a 10-cent cigar, rolled on the thighs of ... well, you know.