Visit the grave of a relative in central Mexico and you're just as likely to find their body, writhing in apparent eternal agony, mummified and propped up for the amusement of tourists than resting in peace.

The Guanajuato Mummy Museum, which sees more than 4,000 visitors a week, charges tourists £2 to gape at more than a hundred dried human cadavers, all of which have been disinterred from graves in the cemetery next door.

Behind flimsy glass cabinets, the museum displays murder victims, criminals who were buried alive and infants laid to rest dressed up as saints – a Mexican belief that it will ease their passage to heaven.

'It's terrifying, I feel sick to my stomach,' Peruvian visitor Maria Goncalves told MailOnline in the middle of her group's guided tour. 'It's the terrible expressions the mummies all have that makes it so horrible.' 

The Guanajuato Mummy Museum - owned by the state government - was recently voted as one of Mexico's best tourist attractions by users of one of Mexico's most popular tourism websites.

The mummies are a parchment-yellow colour, their dried skin moulding around the bones which lie beneath the surface.

The thinner areas of skin – such as the eyelids, genitals, cheeks and earlobes – have deteriorated faster, and in most cases little remains but flaky scraps and gaping holes.

Despite the museum's macabre exhibit, guided tour groups of 15 or more pass through its hallways every ten minutes.

'We see even more on weekends,' says Jose Martínez, who sells souvenir sugar effigies of the dried human remains at the museum's exit. 'Usually on Saturdays there's an hour-long wait just to get in.'

The human remains have been preserved due to the method of burial in the Saint Paola Cemetery next door.

Corpses, rather than being buried in the ground are sealed inside air-tight crypts, where the lack of oxygen slows the natural rate of decomposition.

'The bodies dry out rather than putrefy, which leaves them in this state of mummification', says Jesús Saltillo, one of the tour guides at the museum.

Many of the corpses are so well preserved that their eyebrows, beards and fingernails are still intact.

Nearly all of the mummies mouths are gaping open, a result of the hardening of the tongue and slackening of the jaw muscles following death.

'It leaves them all with an expression as if they were experiencing terrible pain,' says Jesús, 'but the vast majority died peacefully.'

Those mummies who didn't die 'Holy Deaths' – as the Mexicans describe the act of dying in one's sleep – are displayed in a separate section of the exhibit.

One glass case in this area contains three agonised mummies: a man whose fatal stab wound to his abdomen is still a visible puncture in his parchment-yellow skin, a drowned man whose rigour mortis set his writhing legs in the form of a frog's, and an unmarried pregnant woman who was buried alive by her own family, her screaming face covered by skeletal hands.

The Saint Paola Cemetery, the museum's source of mummified remains next door, is made up of entire walls of individual crypts, seven tombs high. Those which are occupied are bricked up from the outside and sealed with a placard denoting its occupant, those which are empty leave dark square holes in the flower-decked facade.

When a family's lease on their loved one's crypt expires, they are given five days to renew the payment (£95 for twenty years).

If they choose not to pay, the body is removed and given to the museum's curator for inspection. If the curator finds it's condition good enough to appeal to the huge numbers of visitors his museum receives, it is added to the collection.

If rejected, the body is sent to a common grave on the outskirts of town.

The first ever mummy to be disinterred was Remigio Leroy, known as the 'French Doctor', who died during a visit to Guanajuato in the 19th century.

The Frenchman's body was released after twenty years inside a crypt in 1865, when the owners were amazed to find his almost-perfect preservation.

His condition, complete with the clothes he still wears for visitors today, aroused so much excitement in the mining town that the cemetery began to collect other well-preserved corpses for display, eventually establishing the dedicated museum in the 1950s.

The museum is renowned for its ownership of the smallest mummy in the world – a four-month old foetus of a woman who fell victim to a cholera outbreak in the 1860s.

The foetus, no bigger than a pound coin, was found preserved still inside its mother's womb when she was removed from her crypt and is today examined by visitors through a magnifying glass fixed above it.

The most recent addition to the collection was Baby Enrico, an infant who died at six months of age in 1999.

Following the expiration of his crypt's five-year lease, the museum removed him in 2004 and chose to add his body to the collection, thanks to his parents' decision to dress his corpse up as Saint Bartholomew.

His green and yellow tunic and wooden halo are one of the more popular mummified bodies in the museum.

'His parents still come to visit him,' museum guide Jesús tells a horrified tour group made up of Mexicans and Canadians. 'They couldn't afford the cemetery fees any longer, but they occasionally come here to see him.'

Baby Enrico is the second exhibit in the 'Baby Room', where five infants - all less than a year old - are lined up, each in climate controlled display cases, dressed as they were found when their crypts were broken into.

'Little Saint Martin', the final infant in the exhibit, who died at birth and was never formally named, was dressed by his parents as Saint Martin, complete with broom, rosary and homespun cassock, in the hope that his outfit might recommend him to a peaceful afterlife.

Only one cadaver in the exhibit has been disinterred from burial beneath the earth and the difference from its crypt-dwelling counterparts is remarkable: only the skeleton remains.

The museum is open seven days a week, although closes for a day every two months in order to clean the mummies, many of whom are still wearing the clothes they were buried in.

'The clothes begin to rot before the bodies do,' says tour guide Manuel Limón. 'It's vital that they are maintained.'

Those cadavers which are undressed display the yellow skin, shrivelled eyeballs and gaping mouths of Hollywood zombie movies.

Indeed, multiple Mexican horror movies have been made using the mummies as props.

The best know is El Santo vs The Mummies of Guanajuato, which features the most famous wrestler from the country's popular 'lucha libre' sport, taking on the mummies as they come to life, executing perfect pile-drivers into their dried forms.

Another section of the exhibit displays the creepier side of the museum's history. One display exhibits a finger bone belonging to a man who had been murdered and buried in the cemetery next door.

Following the funeral and interment of his suspected killer, the rotted index finger appeared on top of the newly sealed crypt, pointing out his murderer.

Guanajuato, a mining town in central Mexico was once an important city during the Spanish viceroyalty on the North American continent, and was the birthplace of the Mexican Revolution.

Today it's winding streets, mountain tunnels and colourful houses make it one of the country's most popular tourist attractions.

Arturo Tabares, Guanajuato government head spokesperson, defended the museum. He said: 'The museum is an important part of Guanajuato's tourist appeal. The museum breaks no laws in displaying its exhibit to visitors, who are given fair warning of its graphic contents.

'We have a different cultural approach to death in Mexico, here we celebrate the cycle of life and accept death as inevitable. 99% of the visitors leave the experience pleased with what they saw.'

Read the original story on the Daily Mail