Mugshots of prisoners line the walls of the white corridor that leads to what must have been the most feared room in all of Missouri.
Inside the bright, white, airtight chamber are two steel chairs, which these 39 condemned men and women were strapped to at one time or another.
And beneath the chairs are cavities, which used to store the jars of sulfuric acid and cyanide pellets that killed each and every one of them.
This is the old gas chamber at the former Missouri State Penitentiary in Jefferson City - a prison that was once dubbed the "bloodiest 47 acres in America" - and one of Missouri's top tourist attractions.
Each year thousands of tourists visit the former prison and sit in these chairs for obligatory holiday snaps while taking in tours of the 180-year-old cell blocks, the underground death row cells and the site of former buildings that were burned down during a deadly inmate riot at the facility in 1954.
But Missouri State Penitentiary is just one of hundreds of former prisons that have found new life as tourist attractions, museums, ghost tour sites and even hotels, giving the generally law-abiding public a taste of a brutal life behind bars.
While most of us will do what we can to avoid being sent to the slammer, but when it comes to old prison tourism, visitors with a lurid curiosity can't keep away.
"Well, it's like ... this could have happened to me," one tourist at the Missouri State Penitentiary told Reuters.
"You have a fascination with it in some way."
Prison tourism has been a growing trend since the 1990s and is as popular as ever today.
The Tower of London, where Anne Boleyn, Guy Fawkes and the Kray twins were holed up, remains one of the city's must-see attractions. Each day, thousands of tourists wait eagerly on a San Francisco pier for the ferry to Alcatraz, where criminal luminaries such as Al Capone and James "Whitey" Bulger were once dragged in chains.
Last year, California's still-operating San Quentin State Prison created international headlines when correctional officials offered a rare tour of death row, allowing hundreds of condemned men to be photographed as they sat in cells awaiting the outcome of California's debate on the future of capital punishment.
Closer to home, Melbourne's notorious Pentridge Prison - where guided tours remain popular - is about to be partially revived as a boutique hotel that will incorporate the preserved, original cells of the infamous B Division. Other local highlights for tours include Fremantle Prison and Old Melbourne Gaol, where Ned Kelly was hanged and his death mask remains on display.
Globally, there are more than 100 former prisons and jails converted to museums or open for tours, according to the Eastern State Penitentiary in Philadelphia.
A new prison museum will join that list this year. Called Alcatraz East, the soon-to-open museum in Pigeon Forge, Tennessee will be modelled on a 19th century prison and will house impressive artefacts from America's history of crime and punishment such as the Bronco car from OJ Simpson's infamous police chase, Al Capone's rosary beads and the death mask of John Dilligner.
According to Fortune, the huge number of former prisons on display in America is largely due to the explosion in prison numbers across the country during the 1990s. Historic prisons became too small to house the growing number of inmates and they were replaced by new, bigger prisons - and state authorities looked for ways to repurpose the old ones.
"They couldn't afford to demolish [or remodel them]," Michelle Brown, associate professor of sociology at the University of Tennessee, told Fortune.
And so they became attractions for tourists fascinated by the places where convicted men and women languished, rioted, killed guards and each other, or met their maker at the hands of the executioner.
Some museums have sought to educate the public about the evolution of the penal system, but others, Ms Brown said, were just voyeuristic entertainment "based around a really uninformed sense of spectacle".
She told Fortune about a museum in West Virginia where a mannequin was dropped from a gallows, "which thrilled everyone and horrified me".
But others embrace how interested the public is in how prisons have evolved, especially as America continues to debate mass incarceration and the role of capital punishment in some states.
"I think it would be more disturbing if we had [millions of people] behind bars and nobody paid attention or wanted to know what it was like," Lauren-Brooke Eisen from New York's Brennan Center for Justice told Fortune.
Texas Prison Museum in Huntsville, which opened in 1989, draws 32,000 visitors a year who check out its contraband exhibit - including a display of prisoner-made shanks - last statements gallery and, perhaps most of all, Old Sparky - the electric chair that executed 361 Texas prisoners between 1924 and 1964.
"I wasn't a part of this museum when it first opened and I wondered, 'who in the world would want to visit a prison?'" director Jim Willett told Fortune.
"It's all sorts of people. We get people from all over the world. I think people come just to try to learn something about what's on the other side of those walls and fences."
TEN INTRIGUING FORMER PRISONS YOU CAN VISIT
Napier Prison, Napier, New Zealand
New Zealand's oldest prison - built in 1862 and decommissioned in 1993 - Napier Prison is especially popular for its chilling hanging yard and gallows, graveyard and solitary confinement cells, which are all out on display.
It's also said to be haunted. Visitors have reported unexplained footsteps, disembodied faces and doors opening and closing on their own.
The prison's most infamous inmate, mass murder Roland Edwards, is particularly believed to haunt the prison. Paranormal activity is said to be more heightened around the anniversary of Edwards' death.
Alcatraz, California, US
This grim maximum security prison, sitting on an island in the picturesque San Francisco Bay, was a former military prison that operated as a federal prison from 1933 until 1963.
It held big shots such as mob boss Al Capone, Winter Hill Gang leader James "Whitey" Bulger and pimp and murderer Robert Stroud, who became known as the "Birdman of Alcatraz" due to his keen interest in ornithology.
Visitors can check out the prison's cells, hear about prison riots and daring escapes and learn about the island's occupation by Native American activists in 1964 to 1971.
Hostel Celica, Slovenia
This trendy youth hostel in Ljubljana, Slovenia was originally a jail built by the occupying Austro-Hungarian army in 1882.
It remained in use until Yugoslavia fell apart, and when Slovenia became independent in 1991, a group of artists and squatters stopped authorities from demolishing the building. It became Hostel Celica, which means "cell" in Slovene, in 2003.
Each of its 20 cells still have bars on doors and windows and dozens of local and international artists have transformed the rooms into unique spaces.
The basement, which used to be a solitary confinement cell, has been left as it was - cold, without windows and with original graffiti and scratches on the walls.
Robben Island, South Africa
Off the coast of Cape Town, Robben Island served as a colony for lepers and an animal quarantine station but later found infamy as the place where political prisoners, including Nelson Mandela and current president Jacob Zuma, were incarcerated during apartheid.
Mandela was famously released from the maximum security prison on February 11, 1990.
The last prisoner left Robben Island in 1996 and three years later it became a UNESCO World Heritage Site. Guided tours from the mainland are led by former political prisoners.
Eastern State Penitentiary, Pennsylvania, US
This pioneering Philadelphia prison opened in 1829 with the radical philosophy that tough solitary confinement would set prisoners straight. It was said to have set the standard for penal reform worldwide.
Al Capone took a turn inside Eastern State Pen's Gothic castle-like walls, along with notorious bank robber Willie Sutton. The prison's facilities were advanced and it was outfitted with running water even before the White House was.
The prison closed in 1971. Today, its Terror Behind the Walls tours, which run from September to November, are a massive hit with tourists and are said to be the biggest Halloween events anywhere in Philly.
Fremantle Prison, WA
Convicts were made to build their own prison at Fremantle, and the result - the foreboding, pale limestone monolith that is Fremantle Prison - is now a World Heritage-listed building.
The prison was opened in 1855 and some 350,000 prisons were incarcerated here before it closed in 1991. It was the focus for a number of Royal Commissions and in 1988 an infamous riot occurred there, causing $1.8 million of damage.
Highlights for tourists include the Great Escapes Tour, which recounts Fremantle's famous inmates, the spooky Torchlight Tour, and an underground boat tour through the prison's convict-built subterranean tunnels.
Kilmainham Gaol, Dublin, Ireland
Kilmainham Gaol, built in 1796, held political prisoners as well as petty criminals under tough conditions. Men, women and children as young as seven years old were incarcerated here, though many adult prisoners were later sent to the penal colony in Australia.
The prison remains a significant site linked to the Irish independence movement. Most of the leaders of the Irish nationalist leaders were incarcerated at Kilmainham, and 16 executions were held as a result of the 1916 Easter Uprising.
The prison closed its doors in 1924 and now operates as a museum, offering guided tours as well as ghost tours.
Hoa Lo Prison, Hanoi, Vietnam
This prison in Hanoi, in the north of Vietnam, was originally built in 1886 during the French occupation of Indochina.
It was later used by North Vietnamese forces to hold American prisoners of war during the Vietnam War. Those POWs famously dubbed it the "Hanoi Hilton".
One of its most famous prisoners was US Republican senator John McCain, who was held there for several years after his plane was shot down during a bombing campaign.
Museum collections include an extensive array of war weapons, the original guillotine used by the French colonists and the interrogation room for American prisoners of war.
Maitland Gaol, East Maitland, NSW
This prison officially opened in 1848 and by the time it closed in 1998, it was the longest continually run jail in NSW.
It was the scene of daring escapes and violent riots by prisoners, including a particularly bloody riot in 1975.
Floggings occurred in the early days of the prison and in 1861 the public were welcomed to witness executions by hanging at the main gate. Sixteen men were hanged at the prison between 1849 and 1897, all for murder or rape.
It's now a major tourist attraction in the Hunter Valley. Visitors can opt to sleep over for a night, which includes getting "locked down" in a prison cell.
Dachau Concentration Camp Memorial Site, Dachau, Germany
In 1933, during the Nazi rule of Germany, the prison complex at Dachau was built to accommodate the overflow from jails, and was intended to hold political prisoners.
It evolved into a slave labour camp and its entrance was emblazoned with the Nazi slogan "Arbeit mach frei", which generally translates to "Work sets you free".
Tens of thousands of prisoners died at Dachau, although it was not an extermination camp like others operated by the Nazis.
About 30,000 prisoners were at the camp when it was liberated by Allied forces in 1945.
It is now a well-visited memorial site, and visitors can explore the sprawling grounds and see the cells where prisoners were held.