There are plenty of pristine, idyllic landmarks for you to visit on this planet, but believe it or not, many of the world’s most popular tourist attractions are not very attractive. In fact, some of them are downright... well, yuck.

They say that roughing it is an integral part of travelling, but you need a pretty strong stomach to visit these germ-filled places. Even if there’s a slight chance you’ll get grossed out by remains, weird animals, or exposure to undue amounts of waste, then you may want to think twice before stepping foot in any of these attractions. Seriously.

From the icky to the macabre, despite their grotty reputation, these places still manage to bring in hoards of curious travellers from far and wide, who are clearly not deterred by the plain grossness of them. More than that, they’re even happy to pay for the yuck factor.

If you're not averse to that sort of stuff, have a strange curiosity for all things vile, and think swimming in a pool of sake with a bunch of strangers sounds like a good time, then check out some of these landmarks from around the globe. Jumbo-sized bottles of hand sanitiser at the ready.

25 25. A 750-Sq-Ft Brick Wall Covered In Saliva: The Seattle Gum Wall, USA

Down an unassuming alleyway next to Seattle's famed Pike Place Market is a hidden work of art or, as we like to call it, a sticky mess of gum and spit.

Started in the 1990s when local patrons in line for an improv show at Post Alley’s Market Theater stuck their used gum on the wall, the gum wall has grown piece by piece to cover an enormous expanse of brick wall.

Sure, it’s a colourful display, but the stench of decaying and aged chewing gum can be a bit offensive. Despite this, however, it is now one of the city's top tourist draws, according to The News Tribune, attracting many selfie-shooting visitors each keen to leave a wad a gum of their own.

24 24. Think Twice Before Kissing The Blarney Stone, Ireland

Legend has it that kissing this rock will give you the gift of the gab, but considering the number of people who lock lips with this stone every day, you’re more likely to get the gift of disease.

The Blarney Stone, which is in Blarney Castle outside Cork City, is one of Ireland’s most famous tourist attractions and draws more than 300,000 tourists a year. Clearly, these people have never heard the rumour that locals sneak in after-hours and urinate on the rock, just to mess with tourists. Kiss this rock at your peril.

23 23. A Kiss Too Far: Oscar Wilde’s Tomb, Paris

“A kiss may ruin a human life," Oscar Wilde once wrote. As it turns out, a kiss (or a few thousand) nearly ruined the Irish dramatist's tomb.

Up until 2011, when measures were taken to protect the tomb, kisses in lipstick left by admirers had been eroding and destroying the memorial, which is in Paris's Père Lachaise cemetery. Grease from the lipstick had sunk into the stone and every time it was cleaned, more stone would wear away.

Since the practice was outlawed, a glass panel was installed to deter would-be lawbreakers from planting a smooch. But with all that spit, would you even really want to?

22 22. A Display Of Human Hair: Leila’s Hair Museum, Missouri

Old hair tends to be one of those things that can really gross people out. If this is you, avoid Leila’s Hair Museum, which is dedicated entirely to the art of hair.

Though turning hair into wreaths was something of a Victorian obsession, hair art actually dates back to at least the 1400s. In an age before photography, collecting hair was a way of capturing the essence of a person at a point in time, and keeping the memory of a deceased loved one near.

The museum has over 2,000 items, including wreaths and jewellery, created from human hair that date back to the 17th century. It’s basically lots of perished people’s hair.

21 21. Yes, They Smell: The Venetian Canals, Italy

It’s one of the most romantic cities on the planet and its canals are one of Europe’s most recognisable landmarks. But these waterways are also completely and utterly stank.

Venetian waters are really quite polluted, which is one of the main reasons why swimming is discouraged. Venice was characterised by an open-air sewage system in a not-so-distant past, meaning that the vast majority of raw sewage produced by Venetians was flushed directly into the canals.

Although waste management has improved, the water is nowadays choked with manmade chemicals like laundry detergent and motor oil.

If you must see Venice, do yourself a favour and enjoy its majesty from the comfort of a gondola. Keep those hands out of the water.

20 20. Not As Cute As They Look: The Barbary Apes of Gibraltar

The famous monkeys who inhabit this British Overseas Territory roam the Upper Rock area of the Gibraltar Nature Reserve. The five troops, comprising roughly 300 macaques, are considered by many to be the top tourist attraction in Gibraltar, despite the fact they can actually be quite aggressive, according to the BBC.

They will often approach and sometimes climb onto people, as they are used to human interaction, and they have been known to fling their own waste with surprising accuracy. Monkey poo in your face is not a good look.

19 19. Pay To See Toxic Waste: Berkeley Pit, Montana

The Berkeley Pit is a former open-pit copper mine in Butte, Montana, and now one of the only places in the world where you can pay to see toxic waste.

What your two dollars entry fee will get you is a view of the pit from a platform located above it. You'll see a reddish, luminous body of water heavily polluted by acids and toxic heavy metals, making it extremely contaminated.  It looks intriguing, but this place is deadly.

18 18. Human Soup? Hakone Kowakien Yunessun, Kanagawa, Japan

Japan has a centuries-old tradition of traditional bathhouses. So far, so normal. But this hot spring theme park, located in the famous sight-seeing area Hakone in Kanagawa Prefecture, gives the concept a pretty gross twist.

This is not a place to go if you can't handle a crowd of people swimming in your favourite drink, because that’s precisely the service this place offers.

You can pick among 25 different baths, including green tea, coffee, red wine, sake and miso soup. In fact, the wine pool is so sought after that it’s only open for 12 days a year. No thanks.

17 17. A Labyrinth Of History: Catacombes De Paris, France

Paris might be the city of love, but below the city streets is a large labyrinth of underground tunnels and passageways that snake across the French capital. What’s gross about that, you may ask? Well, inside them rest the remains of more than six million people.

By the 17th century, Paris’ cemeteries were overflowing. The solution was to put their perished in the tunnels that had existed beneath the streets of Paris since the 13th century, remnants of a time when limestone quarries were mined to build the city.

Some of the tunnels are lined to the ceiling with skulls and bones. You are literally surrounded by people of past centuries.

16 16. Spiritual But Unsanitary: Ganges River, India

The Ganges is India's holiest river, considered a source of spiritual purification for devout Hindus. But today the river is among the world's most polluted.

Raw sewage, plastic bags and bottles, industrial effluents, human waste, chemicals from tanneries, discarded idols, cow dung, garlands of flowers, animal carcasses, butcher’s offal, chemical dyes from sari factories and construction waste - the levels of gross are too many to count. You should probably think twice before taking a dip.

15 15. Bones, Guts And More: Mütter Museum, USA

Philadelphia's Mütter Museum claims to be America’s finest museum of medical history. Founded in 1858, it includes a human skull collection, Grover Cleveland's jaw tumour, Einstein's brain, a wax model of a syphilitic face, a massive 40-pound human colon, and more. Let’s not forget, there’s also the Soap Lady, who gets her name because, after passing, all of her body's fat underwent saponification, which means it was literally turned into soap.

The goal of the museum is to help visitors understand the mysteries and beauty of the human body and appreciate the history of diagnosis and treatment of disease. Sounds worthwhile, but have you got the stomach for it?

14 14. Punk Rock’s Petri Dish: CBGB’s Toilets, New York

CBGB was a New York City punk club which opened in Manhattan's East Village in 1973. Although the club closed in 2006, its toilets still remain the stuff of legend and punk fans still flock to the building, which now houses a clothing store.

Back in its heyday, its two bathrooms were gross enough to make even the most road-seasoned musicians take a step back. These stool gardens became so famous that the Metropolitan Museum Of Art included a re-creation of them in its “PUNK: Chaos to Couture” exhibition.

13 13. A Temple Full Of Rats: Karni Mata Temple, India

The rat temple has roughly 20,000 furry residents, all supposedly reincarnated Indian storytellers and descendants of the Karni Mata, an incarnation of the god Durga.

Shoes aren't allowed inside, so you may end up treading in rat poop. Worse still, visitors are encouraged to drink the rats’ drinking water and eat their leftover food, both of which supposedly bring good luck. How far will you go for some good fortune?

Come before sunrise or late at night, when the rats come out to gather food, to see the temple overrun by the rodents.

12 12. The Pigeon Problem In St. Mark’s Square, Venice

This gorgeous piazza in Venice is known for its pigeons, which are both a nuisance and extremely unsanitary. Pigeon droppings became such a problem that the Italian authorities implemented a feeding ban in 2008 to try and protect their UNESCO city status.

But despite the presence of security officials and punishments ranging from a verbal warning to a €700 fine, there are still many visitors who don’t think twice before throwing a little something snack for the birds.

The food ban hasn’t deterred the pigeons either. Today, the pigeons have formed colonies throughout the city, and the estimated 100,000 birds far outnumber Venice’s 60,000 human residents.

11 11. Who Knew Sewage Could Be So Fun? The Sewer Museum, Paris, France

The Parisian sewers have long fascinated tourists, and were first opened to the public during the World Exposition of 1867. The even used to tour the system on boats, in a sort of Parisian answer to the gondola.

Today, the Parisian sewer system is closed with the exception of the Sewer Museum, where visitors can watch actual drain water swirl around them and can tour a functional septic tank. If you can handle the moderate odour, you might find this museum surprisingly interesting.

10 10. Don’t Touch That: Grauman’s Chinese Theatre, Hollywood

George Clooney, Clint Eastwood and Marilyn Monroe are among the superstars with their handprints moulded into the concrete of the forecourt of Grauman's Chinese Theatre, now the TLC Chinese Theatre, in Los Angeles.

Since 1927, celebrities have been asked to leave imprints in the cement, and the sidewalk is now littered with 246 celebrity hand and footprints that draw in five million visitors a year, according to the LA Times.

That’s a whole lot of people sticking their grubby mitts into these indentations - do you really want to join that club? Don’t forget the hand sanitiser.

9 9. Pucker Up: St. Peter’s Basilica: Vatican, Italy

This bronze statue commands the hands and lips of those who come to visit it. Located inside St. Peter’s Basilica, this statue was made by Arnolfo di Cambio way back in the 13th century, and people make a beeline for its feet. They touch and or kiss his foot while praying for a blessing. Does that blessing come in the guise of a cold sore, by any chance?

These days, a guard is on watch to keep the flow of people coming in moving steadily, but the statue’s right toes are literally worn down by centuries of pilgrims touching the foot.

8 8. A Cave Full Of Human Hair: Avanos Hair Museum, Turkey

Caves are creepy enough. Add to that 16,000 samples of human hair, and things take a turn for the gross pretty quickly.

Located in the Cappadocia region, an area renowned for its stunning underground cities and ceramic art, this museum was founded by Turkish potter Chez Galip.

It all started when he said goodbye to a friend and asked for something to remember her by. She cut off a lock of her hair. And so, every woman who heard this sad story came by his shop and offered him a lock of her hair as well. Approximately 38 years later and the museum has amassed quite the collection.

7 7. Locking Lips With Marilyn Monroe’s Crypt, Los Angeles

Monroe’s earthly remains are interred in crypt number 24 in the Corridor of Memories, a complex of above-ground crypts on the west side of Pierce Brothers Westwood Village Memorial Park, Los Angeles.

Her final resting place was intended to be modest and private, but the power of her popularity continues to draw visitors more than half a century later. A steady stream of visitors and admirers continue to plant their lips on the cold, likely germ-infested, marble slab fronting her final resting place. More than 50 years of kisses have dyed the grey stone pink. This once sweet gesture is now just a bit unsanitary.

6 6. Paradise Lost: Kuta Beach, Bali, Indonesia

After China, Indonesia is the second-biggest marine polluter in the world, contributing 10% of global marine pollution, according to Environmental Health Perspectives. So it shouldn't be much of a surprise to learn that Kuta Beach, one of Bali's most popular tourist destinations, is often covered in garbage.

In fact, the problem got so bad that in 2017 the island declared a "garbage emergency,” after authorities realised that the volume of plastic being washed up was endangering the tourist trade.

Workers were sent to Jimbaran, Kuta and Seminyak beaches, and were carting off up to 100 tons of junk each day at the peak of the cleanup, The Telegraph reported.