I have a recurring real estate dream in which I find an extra room in my home, tucked behind a door I have never noticed before.

The décor inside is usually worn and dated, with shag carpeting, wood paneling and terrible lighting. But the room’s potential never escapes me. All my clutter troubles are solved. Finally, I have space.

Then I wake up to a reality shared by many New Yorkers: There are no hidden rooms to house all the junk currently shoved in those plastic bins under the bed.

But I’m not the only one dreaming about newfound and secret rooms. Tales of hidden spaces and passageways have long held a place in city lore, capturing our collective imagination. Dignitaries, including Franklin D. Roosevelt, once used a train platform tucked beneath the Waldorf Astoria to discreetly access the hotel. The prohibition-era speakeasy “21” has a disappearing bar and secret wine cellar that it boasts about on its website — not such a secret anymore.