Twice a day I move between the walls of a prison.

That is to say the train on which I commute to and from New York City trundles between the walls of Sing Sing Prison, which dominates a bluff overlooking the Hudson River in the Westchester County town/village of Ossining.

Sing Sing is a name known around the world.

It is the original “Big House” dating to the 1820s, onetime home to the notorious “Old Sparky” electric chair, and, for a few years after World War I, the residence of Irish labor leader James Larkin.

It’s still an active prison all these years later; indeed it’s an entirely maximum security facility as the former medium security part was phased out some time ago.

The prison is in two parts, upper and lower, the former on the high ground rising from the Hudson, the latter down at the river level.

The train tracks run between the two.

If Sing Sing was private land open for residential development it would be off the charts pricey.

But it is owned and run by New York State and doesn’t pay taxes to the town or village of Ossining.

But there are plans for a museum and studies have shown that such a thing could be a veritable goldmine, especially if the museum actually penetrates the current outer wall and incorporates the still standing shell of the original cellblock.

There’s something about prisons that draws people, and by that I mean those who would never in a million years want to be sent to one.

Hollywood has long viewed prison dramas as guaranteed sellers.

And as much as the idea of prison repels most, it also has an irresistible allure for many who try to imagine what life is like behind those walls and all that wire.

America, of course, has quite a few prisons that make the famous grade.

Alcatraz immediately comes to mind.

Then there’s Folsom – raised to the rafters of fame by Johnny Cash - Leavenworth, Angola, Pelican Bay, Attica, to name but a few more.

And there is Sing Sing.

So what would Ireland’s entry to the most famous/infamous prisons in history be?

Leaving aside Long Kesh, which most today would say was not a normal prison in the first place, there are not many facilities that would hold up against the notoriety of Alcatraz and its ilk

Mountjoy Prison in Dublin certainly has a story to tell.

I was inside “The Joy” once -- to report on prisoners putting on a play, I should add.

Mountjoy (originally Mountjoy Gaol) dates to 1850 and was modeled at the time on Britain’s Pentonville.

It’s for sure famous in Irish terms but blends into the city around it. Not blending and absolutely standing out is another Irish prison, a facility which actually does rival Alcatraz, at least in terms of a location.

That would be Spike Island in Cork Harbor.

It’s a name to remember for starters, and it’s a name that lately has been attracting many visitors.

Come and go types. Spike Island is no longer an active prison.

More than 10,000 people have set foot on Spike Island this month alone according to a report in the Irish Examiner.

Spike Island has quite a history. It was once a monastery (that would be the 6th century) and then a fortress before becoming a prison.

Back in the days of Cavaliers and roundheads, the dreaded Oliver Cromwell used Spike Island to, well, “house” some of the Royalist prisoners.

The first fort was erected on the island in 1779, this as the uppity American colonists were having their own go at British royalty.

Later, with Napoleon stomping around Europe and threatening to invade Britain, quite possibly using Ireland as a back door, the island saw the creation of Fort Mitchell, one of the largest star-shaped fortifications in the world and the structure which would be converted to a prison during the 1840s.

By 1851, according to the Examiner report, Spike Island was the largest prison in the British Empire, most likely the world, with 2,300 prisoners crammed into its inadequate cells.

“Conditions were appalling….thousands of convicts are buried in mass graves on the island and the period is a dark chapter in British penal history.”

What was now a notorious British penal institution is now an Irish tourist attraction.

Such is progress and the passage of time.

The main attractions, said the Examiner report, are the 1850s punishment block, a former prison used to punish unruly prisoners, the 1985 cells and riot exhibition, six-inch guns that guard the harbor and the recreation of a transport ship’s hull.

Ah, that 1985 riot.

And yes, you guessed correctly.

I was there.

But Sin sceil eile, a story for another day.