My latest architectural obsession is the cupola. Strictly defined, a cupola is a domelike structure surmounting a roof or dome, often used as a lookout or to admit light and air. You may see them on the rooftops of barns or churches, and you can certainly find elaborate versions of cupolas incorporated in the architecture of many public buildings in the United States and throughout Europe; the dome of Capitol Hill in Washington, DC, is probably the best known cupola in America.

But my interest is in the residential cupola. It was Martha’s barn at Turkey Hill that first piqued my interest in this architectural feature. When I first saw pictures of it I would imagine how amazing the gardens would look from the windows of her cupola, and I had read that you could see all the way to the ocean from that perch. In 2002 I wrote to the editors of Martha Stewart Living urging them to do a feature on that barn, including the cupola. My advice was never taken, sadly, so I never did get to see inside that little dome – and I likely never will, now that Turkey Hill has been sold.

The cupola on top of Martha's guest-house 'barn' (left) must have had an incredible view.

In house plan books, which I tend to collect, I scour the pages for plans that have cupolas. Most of them, unsurprisingly, are mansions, but some of them are elegant country homes or small Newport classics. Homes that have cupolas have a sort of neo-European flavour to them or a maritime, northeastern charm. There is a large brick home just outside of Toronto that I pass every time I visit friends there. It has an enormous square cupola, fronted on all four sides with beautiful panes of leaded glass, framed in dark wood. All around the house there are rolling fields. If it was my cupola, I’d make it my secret reading tower and furnish it with only the basics: a big, comfortable chair, a small table for my tea and a sturdy reading lamp. Don’t bug me until I turn the last page.

The Cupola House in Edenton, North Carolina.

The plans for a cupola reveal the curvy stairs that lead to its cozy peak.

This urban cupola is very classic. It leads from an adjoining apartment to a rooftop terrace.

Looking from the inside out.