With risks involving everything from toxic fumes to deadly heat, these natural attractions certainly aren’t for the fainthearted.
DailyMail.com has scoured the globe for a collection of wonders which tourists are warned to approach with extreme caution.
Most recently, Costa Rica’s Cave of Death or ‘Cueva de la Muerte’ made headlines with inquisitive tourists flocking to see the cavern which emits carbon dioxide and instantly kills any creature that enter.
But equally as toxic is the sulfur lake at the Kawah Ijen volcano in East Java, Indonesia, which would kill anyone if they fell in.
From caves to volcanoes to ice-capped mountains and spots in between, take a trip down to see the wonders you should be wary of.
Gates of Hell, Turkmenistan
The Darvaza flaming gas crater in Turkmenistan has been burning for close to 50 years
Nicknamed the Gates of Hell, the Darvaza flaming gas crater in Turkmenistan is a sinkhole 100ft deep and 130ft wide, which formed when the Soviets were drilling for natural gas.
The upper layers of soil collapsed into an underground cave, opening a large hole filled with gas.
To avoid gas poisoning local people and livestock, geologists ignited it. They believed the fire would subside within weeks but the whole crater has been burning for close to 50 years.
In November 2013, it was found by Canadian explorer George Kourounis that unique bacteria survive at the bottom of the crater despite the roasting temperatures.
Kourounis was the expedition leader on behalf of National Geographic as part of a project which involved going inside the crater and gathering soil samples for DNA analysis.
This was to look for ‘microscopic life forms that are capable of surviving in these intensely hot, dry conditions,’ Kourounis explains. It took a year and a half of preparation and getting government permission.
To get into the crater, Kourounis and his team stretched fire-resistant ropes across the flaming pit and he was able to go out on the ropes, using pulleys and wearing a heat-protective suit with a self-contained air tank.
Then he had to rappel down to the bottom, where he had 17 minutes to collect his samples, take some temperature readings and get out safely.
Thousands of tourists also flock to the site every year to snap fiery photos from the sidelines. While the crater is one of Turkmenistan’s main tourist attractions, it is also a cause of environmental blight with vast quantities of harmful methane released into the atmosphere.
Naica Crystal Cave, Mexico
Cave of the Crystals in Mexico were discovered by two miners looking for lead
The Cave of the Crystals in Mexico is connected to the Naica Mine, below the surface of Naica, Chihuahua, where explorers can marvel at massive beams of selenite.
Discovered by two miners looking for lead, the stunning white beams of gypsum have been growing at a snail’s pace for hundreds of thousands of years and some now measure more than 30ft.
The huge mines at Naica have been excavated for years, but in 1975 a massive area was drained so mining operations could take place and the incredible collection of gypsum was discovered.
The formations took shape when super-heated water began cooling and became saturated with gypsum. Over time, crystals formed in the water. One of the major problems still facing scientists wishing to study below the ground at Naica is the heat.
A hot spring located close to the Crystal Caves means the temperature is too hot for people to remain in the crystal chamber for longer than ten minutes at a time. Fortunately, other sections of the mine are air-conditioned.
Canadian explorer Kourounis is one of the few people who has dared to enter the cave and he told DailyMail.com it was one of the wildest experiences of his life.
He explained: ‘The air temperature inside reaches 122F (50C) with a relative humidity of approaching 100 per cent making the air inside feel like 228F (105C)! We had to wear special ice-filled suits to enter the cave for brief explorations.’
Kawah Ijen Volcano and Sulfur Mine, Indonesia
The Kawah Ijen volcano is known for its rich sulfur deposits which are being quarried
The Kawah Ijen volcano in East Java, Indonesia, contains the world’s largest acidic volcanic crater lake, famous for its turquoise color. It has a pH level of 0.5.
The active crater is known for its rich sulfur deposits which are being quarried.
The volcano is one of several active stratovolcanoes – a volcano built up of alternate layers of lava and ash – constructed over the 12.5 mile wide Ijen caldera, the largest in Java.
Eruptions from Ijen are very hazardous because of the risk of the lake draining to form catastrophic lahars, destructive mudflows on the slopes of a volcano.
Coffee plantations cover much of the Ijen caldera floor, and tourists are drawn to its waterfalls, hot springs, and dramatic volcanic scenery.
Men working in the Ijen volcano range have a short life expectancy due to the punishing conditions they face every day in the depths of the mines.
They wear nothing other than t-shirts and trousers as they collect the yellow material, despite toxic fumes being given off and the fact that the molten sulfur is heated to more than 240F (115C).
They must also avoid the deadly turquoise-blue lake which takes up most of the crater floor, as it is made up of almost pure sulfuric acid, and would instantly kill anyone unlucky enough to fall in.
Sulfur is a natural source of sulfuric acid, and is used by oil refineries and in the production of goods such as detergents and fertilizers. It is also a key ingredient in match heads.
Slot Canyons, Zion National Park
Flash-flood fatalities are in Zion are fairly rare, but visitors are warned to be very cautious if wet weather is on the horizon
There have been multiple deaths in the slot canyons of Zion National Park in Utah due to flash flooding. In 2015, seven hikers were swept to the deaths in the area of natural beauty.
The discovery of their bodies capped three days of searches by more than 60 park rangers, sheriff’s deputies and emergency personnel from several agencies.
Park officials said all the victims were hiking together on a day trip through narrow Keyhole Canyon, a challenging route on the east side of Zion that requires canyoneers to swim through several pools of water and rappel steep slopes.
While the group obtained its permit for the trip, there were weather warnings at the time and the National Weather Service had forecast a 40 per cent chance of rain and the probability of flash flooding.
Despite the 2015 tragedy, and another in 1963 which claimed five lives, flash-flood fatalities are in Zion are fairly rare.
The most recent incident occurred in 2022, with an Arizona woman swept away when she was attempting to navigate a section known as the ‘narrows.’
The National Park Service has various advisories on its website in a bid to prevent future disasters from happening. It warns visitors: ‘Traveling into the Virgin River Narrows, even on short trips, can be challenging and risky and requires careful planning before you begin. Your safety depends on your own good judgment, adequate preparation, and constant observation.
‘Flash floods, often caused by storms miles away, are a very real danger and can be life threatening. During a flash flood, the water level rises quickly, within minutes or even seconds.
‘A flash flood can rush down a canyon in a wall of water 12ft high or more. Know the weather and flash flood potential ratings before starting your trip. If bad weather threatens, do not enter a narrow canyon.’
Kaaterskill Falls, New York
Kaaterskill Falls in New York lures visitors with its natural beauty and people have perished while attempting to snap a selfie
Kaaterskill Falls in New York has been deemed one of the most dangerous natural wonders in the world, with multiple deaths over the years.
The vacation rental site Holidu notes that the falls lure visitors with its natural beauty and people have perished while attempting to snap a selfie.
It explains: ‘Of waterfalls, it is not the world’s widest or the longest drop that is the most dangerous. Instead, a picturesque two-stage waterfall in the Catskill Mountains of New York.
‘It is this beauty that makes it so dangerous though, with reports claiming that the last four people who died at Kaaterskill Falls were either taking or posing for a picture.’
In recent years, the New York State Department of Environmental Conservation has planned ways to bring down the number of fatalities.
Despite adding a viewing platform, hand rails, warning signs and a bridge, there are fears the area is still a risky place for those hoping to get a good picture.
The state has also used funds to make two parking lots bigger to stop cars lining prohibited areas.
The Danakil Desert, Ethiopia
With violent volcanoes, blistering air temperatures, toxic gases and land masses being ripped apart by enormous planetary forces, Ethiopia’s Danakil Desert is an unlikely tourism hotspot but that’s exactly what it has become
Ethiopia’s Danakil Desert is home to one of planet earth’s most extreme environments and has been dubbed the ‘cruelest place on Earth.’
With violent volcanoes, blistering air temperatures, toxic gases and land masses being ripped apart by enormous planetary forces, it’s an unlikely tourism hotspot but that’s exactly what it has become.
A number of adventure tour companies take intrepid travelers inside the active territory, which is the considered one of the most volatile places on the map.
Instead of palm trees, sun loungers and five-star accommodation, visitors are greeted with a bizarre combination of sights that look like nowhere else on Earth.
One of the highlights is a massive sulfuric lake. Nicknamed Yellow Lake by Africans – because of the striking color – the phenomenon is caused by high sulfur in the volcanically active region.
Another point of interest is Erta Ale, which is a continually erupting basaltic shield volcano with an active lava lake.
Looking like a scene of biblical destruction, one of its pits is known as the ‘gateway to hell.’
And nearby are incredible salt plains. With little life there – because the salt kills vegetation – it makes Danakil seem even more extra-terrestrial.
Khumbu Ice Fall, Nepal
The Khumbu Icefall on Everest’s Nepalese side is an ever-shifting expanse of glacial ice that requires climbers to navigate crevasses over rickety ladders
Of Everest’s entire route, the Khumbu Icefall receives the most headlines for the danger involved with its crossing.
The area involves a dangerous, ever-shifting expanse of glacial ice that requires climbers to navigate crevasses over rickety ladders, and huge overhanging ice that can be as big as 10-stories high.
While some climbers have perished by falling into crevasses, avalanches are the biggest risk in this area.
Touching on the Khumbu Icefall’s dangerous reputation, the Himalayan Database notes: ‘The 1970 serac collapse as well as other accidents in the Khumbu Icefall during the 1960 to 1980s gave it the reputation of being most dangerous part of Everest.’
Three Sherpas died in 2006 due to a serac collapse and one more in 2009 due to an ice collapse off the West Shoulder.
Then in 2014, an immense tumbling wall of snow, ice and rock killed 16 Nepali guides on the Khumbu Icefall in one of the deadliest accidents in the Himalayas.
This accident shut down the Everest climbing season in Nepal.
Trolltunga, Norway
Trolltunga in Norway juts out 2,296 feet above a glistening blue lake, and many people dare to venture to its tip for a photo
Trolltunga – which translates to troll tongue – has become one of Norway’s most popular attractions in the age of Instagram.
The spectacular tongue-shaped rock formation juts out 2,296 feet above a glistening blue lake, and many people dare to venture to its tip for a photo.
However, Norwegian rescue services are often called out to Trolltunga as tourists clamber to take pictures without preparing properly for the long climb.
One of the world’s top climbers was slammed in 2016 after posing for a photo while swinging from the rock promontory.
Champion Norwegian climber Magnus Midtbo, now 35, posted the image on social media after a climbing trip to the popular tourist attraction.
‘Treating my legs with a much needed break after a long hike,’ he commented on the dangerous stunt, which saw him hang from the end of the rock with his arms.
He did however issue a warning to his followers in the photo caption, writing: ‘I’m wearing a harness and a rope. Please never try this yourself.’
The last reported death at Trolltunga was in 2015, when Australian student Kristi Kafcaloudis, 24, slipped and fell to her death while having her photo taken.
Cave of Death, Costa Rica
Costa Rica’s Cave of Death – or ‘Cueva de la Muerte’ in the local Spanish – is located at the Recreo Verde tourist complex in the district of Venecia
From the entrance, it looks almost like a normal cave, with a rocky overhang and leaves scattered around the entrance.
The only giveaway is a warning sign adorned with deathly skulls and crossbones saying: ‘Danger! No trespassing beyond this point.’
This is Costa Rica’s Cave of Death – or ‘Cueva de la Muerte’ in the local Spanish – located at the Recreo Verde tourist complex in the district of Venecia. Measuring 6.5 feet deep and nearly 10ft long, it instantly kills any creature that enters it.
However, this isn’t deterring brave explorers from making the visit to the site in the hunt for social media videos.
According to Belgium-based cave explorer Guy van Rentergem, who visited the site several years ago, it contains a substantial amount of carbon dioxide (CO2).
In fact, levels of the gas inside the cave are so high that it can cause unconsciousness almost instantaneously, followed by cessation of breathing.
Luckily, humans are generally safe because it’s too small to fit into – and signs on the site provide a sufficient warning.
However, snakes, birds, rodents and other small creatures quickly die after unwittingly wandering into the entrance, perhaps in search of food. It’s unclear exactly what the source of the gas is, although van Rentergem says it is of volcanic origin.
During his visit to the Cave of Death, one of van Rentergem’s crew demonstrated the cave’s potency by holding a lit torch to the entrance.
After just a few seconds, the flame is extinguished – and that’s because CO2 displaces the oxygen around fire that makes it burn.
