We live in a world that is full of incredible landmarks, many of which are manmade and some were created by Mother Nature. Some of these wonders have been around for thousands of years while others have only been around for a few decades. But the world’s landmarks have drawn visitors from all over the world to marvel at their incredible existence. These places have kept us in awe of their historical significance or simply because they continue to functionally operate today in some important capacity. Either way, we are constantly inspired by what they represent.

With so much reverence and importance to the world, these sites will continue to attract tourists, which is actually a double-edged sword for the cities that house them.

The visitors are a major source of economic stability, but they are also one of the biggest reasons for the slow and eventual deterioration of our most treasured sites. People aren’t the only ones who endanger the world’s most famous landmarks, as weather, time and other variables are to blame as well, but it’s no secret we certainly are the leading cause.

Here are 25 world wonders that are coming apart.

25 The Great Wall of China is unstable

Long considered one of the greatest achievements in architecture, the Great Wall of China is truly a wonder of the world, dating well over a thousand years. For a structure that has been around since the beginnings of civilized societies, it’s incredible that the wall is still standing.

But the reality is that not all thirteen thousand miles of the wall are still standing tall as they once did for so long. There are portions of the structure that have started to dilapidate and even outright have collapsed in others.

With so much use by millions of yearly visitors, the wall has begun to suffer and it’s become evident that some areas are simply dangerous. Thankfully, there are efforts to restore the most damaged portions of the Great Wall.

24 Venice is flooding and there's nothing we can do about it

Although Venice is not technically a landmark, it makes the list since the city is a famous tourist destination the world over. Venice is well-known for its incredible layout as a city quite literally built on water.

The main source of travel throughout is by gondolas on the waters that weave through the city. The unfortunate truth is the very makeup of Venice is what is causing its own eventual demise.

As one would likely assume, a city built on water might one day sink under water. Well, that’s exactly what’s happening.

Flooding is a normal occurrence and the rising levels of the water will one day overtake the structures that make up Venice in the not so distant future.

23 Mount Rushmore is falling victim to mother nature

Sculpted in 1941, the famous faces of Mount Rushmore have overlooked the Black Hills of South Dakota for almost eight decades. In those nearly eighty years, the carvings of the famous four presidents have slowly started to lose their pristine and clear shapes.

The culprit here is Mother Nature’s winds which have eroded the rock away. The mountainside is regularly maintained to ensure the faces of America's icons continue to keep their distinct shape.

22 Brooklyn Bridge can't handle the immense traffic

The Brooklyn Bridge is one of the oldest suspension bridges in the world, standing since the late 1800’s in New York City’s East River. The bridge is nearly one hundred fifty years old and is also one of the busiest in the world.

With the age of the structure along with the intense amount of traffic with well over 100,000 cars and pedestrians a day, the bridge is under significant duress. Officials have stressed over the Brooklyn Bridge’s structural integrity for quite some time now, sighting instances of portions falling down into the bay and onto the street, causing major injuries.

21 The Statue of Liberty Is changing color

Lady Liberty is one of New York City’s most recognizable landmarks. In fact, she is probably one of the most famous in the world as her stance in the New York Harbor is as iconic as any structure ever built. Standing tall for a century now, she is still structurally sound, but her color continues to be a source of headaches for the city.

Made of copper, the salt from the Atlantic Ocean she sits in has turned her into her famous green color, but with it, the statue easily attracts all kinds of other unwanted deposits from the ocean, causing it to get dirty, making it sometimes look unattractive.

The city has to regularly work to keep the statue clean as it is common for it to pick up dirt and grime from the ocean and heavy winds in the sea.

20 Leaning Tower of Pisa - Well, this one should be easy

The Leaning Tower of Pisa is known for the very reason it is making this list. Although the tower’s infamous lean attracts millions of visitors eager to take photos with the landmark, it also represents its ever failing structural integrity.

The photos taken here are often lighthearted and fun, but the reality is the Tower of Pisa is, in fact, falling, considering it is leaning at an angle, something buildings should never do. The silver lining is the tower’s popularity keeps city officials very in tune with its safety ensuring that it continues to stand for the money it brings in to the area.

19 The (Crumbling) Pyramids of Giza

Although this landmark is quite easily the one of the oldest on our list, it is one of the most structurally sound of them all. It still appears here though because there are still several documented instances of parts of the landmark crumbling in small sections, most notably the Sphinx statue.

Although they are not in danger of completely falling apart, the possibility of the most important engineering feat in human history coming apart is a constant source of worry.

18 The Sistine Chapel - Michelangelo's art is cracking

Often seen as one of the best paintings ever created, the paintings on the ceiling of the Sistine Chapel have been amazing visitors to the cathedral for over five centuries. Completed over the course of nearly half a decade in 1512, Michelangelo’s masterpiece has started to sustain wear and tear over five hundred years later.

Much of the fading and cracking of the painting was simply nature taking its course, but a big contributing factor is the carbon dioxide released from visitors who are simply breathing in its presence.

There have been major restoration efforts to the frescos which have brought life back into the paintings through painstakingly careful retouches.

17 The Acropolis of Athens - Nothing can withstand time

For a structure that dates back to the start of human civilization, it’s pretty much a miracle that the Acropolis of Athens is still standing today. In fact, it’s still in rather good condition considering it was constructed about 1,500 years ago. Like with all things though, time is undefeated and has slowly continued to erode the buildings that make up the Acropolis.

The Parthenon, the most famous building within the complex has stood tall for what feels like an eternity, but has required upkeep and maintenance as crumbling pieces of the structure are not uncommon.

16 La Guardia Airport, New York - In need of some immediate attention

One of the most trafficked airports in the world, La Guardia of New York City really is a wonder as it has carried hundreds of millions of passengers through the years. But with so much use over the past several decades, it should come as no surprise that it is finally starting to fall apart.

It also doesn’t help that the city has not invested much money into the airport for so long, allowing it to fall into disarray with leaking roofs, crumbling walls, bursting pipes and more.

There have been efforts to fix what needs repairs, but they are often spot jobs to fix one-off problems. The good news is there is a major upcoming renovation of the entire airport in the near future.

15 The Taj Mahal has a darker side

The most visited landmark in all of India, the Taj Mahal is considered the crown jewel as the ultimate testament to love and peace. The white façade and distinct look is synonymous with the country and has been included in countless movies. With such incredible popularity, it attracts several million visitors a year.

With so many tourists making their way to the site, the amount of trash littered throughout has contributed to the overall decline of the landmark. The rising river levels nearby have also affected the structural wooden foundation of the building, furthering the danger to such an important world wonder.

14 Big Ben - More like big scaffolding

The most famous clock in the world is now silent. London’s Big Ben, long an iconic staple of the city and famous to the world, will remain quiet for the next three years as repairs will be made to the Parliament House that it calls home.

The clock itself has also been the source of worry as the hands have come under scrutiny for possible functional issues. After the four years of work are completed, London is confident Big Ben will come back better than ever.

13 The Great Barrier Reef is disappearing

The largest coral reef system at over 1,400 miles long and composed of nearly 1,000 islands, the Great Barrier Reef is one of nature’s greatest wonders. The reef can be seen from space and is not only beautiful, but important to sustaining the ocean life living within it. Due to warming ocean temperatures because of global climate changes seen throughout the world’s waters, big portions of the Great Barrier Reef are starting to disappear.

It has become so widespread that scientists are trying to figure out ways to slow down the deterioration of such an important natural wonder.

12 The Colosseum - People are taking parts of it home

The Colosseum is still the largest amphitheater in the world to this day, even after nearly two thousand years of history on its side. As one of the oldest landmarks on this list, the Colosseum has truly withstood the test of time, still able to hold up to 80,000 spectators.

With so much time passing by, it goes without saying that the structure continues to slowly erode. In fact, part of the stadium’s charm is the half-torn down look and large broken pieces that have given it the very distinct image that is known to the world. The building’s structure is sound for its age, but it is in fact slowly coming apart as to be expected.

11 The Astrodome is infested with rats

Once considered the eighth wonder of the world, Houston’s Astrodome was a marvel that left the world in awe upon its completion over half a century ago in 1965. Since its inception, World Series games, rodeos, NCAA championship games, concerts and so much more have been held at this historic stadium.

Known to the world as the biggest dome-shaped arena when completed, it was considered an architectural achievement ahead of its time. Since then, with the completion of NRG Stadium only feet away and now considered Houston’s new premier venue, the Astrodome has quite literally been deserted and is no longer in use today.

With years of no use, the building has fallen into a state of disrepair with pipes no longer working, the concrete crumbling, strong smells coming from within and reports of rats and other animals taking habitat inside.

10 Penn Station - Cracking floors and bursting pipes

At one time Penn Station was considered one of the premier train stations of the world, picking up passengers in the busiest parts of New York City.

The passage of time has not been kind to Penn Station as it has deteriorated to the point of ridicule by the city’s residents. The walls are coming apart, the floors are cracked extensively with tiles breaking along with maintenance problems throughout. Despite the crumbling station, it continues to be one of the busiest in the world.

9 Notre Dame - An unsupportive underground

Paris’ Notre Dame is often considered the most famous church in the world. The Catholic cathedral was completed in 1260, about 750 years ago, making this landmark definitely one of the older ones on our list. With so much history on its side, the church is finally starting to show signs of time catching up with it. Although the façade is still as beautiful as ever, it’s the parts underground that are beginning to give way with crumbling concrete and walls that most visitors never get to see.

8 Machu Picchu sinks a little bit every day

Peru’s most famous landmark, Machu Picchu is considered one of the great wonders of the world that inspires awe by anyone who pays it a visit. The historic site which was built as an estate to an Incan emperor over 550 years ago is as beautiful as ever high in the mountains of Peru. The fragility of such an ancient city of ruins is also a concern for the country that recognizes that the stones are starting to chip away and move out of place.

Rules prohibiting visitors from jumping for photos to preserve the landmark are in place as well but are not always followed.

7 Trevi Fountain is in need of constant work

The Trevi Fountain in Rome, Italy, is probably the most famous fountain in the world, drawing millions of visitors eager to pose in front of the beautiful Baroque period statues and throw their coins into the water for well-wishing. These crowds have become increasingly popular over time and constant human contact with the stone has begun to wear it away.

The structure’s nearly 250 years is also a major factor in its gradual decline, but there are constant restoration and costly upkeep projects funded by the city, as well as the public, to keep the fountain intact.

6 Angkor Wat - The earth is moving beneath it

Founded in the 12th century, making this monument nearly a thousand years old, Angkor Wat is one of the largest religious sites in the world at over four hundred acres. The Buddhist temple is open to the public for worship and millions visit, making this Cambodia’s prime attraction.

Over time, the ancient temple has sustained deterioration and damage due to a myriad of factors including war damage, theft, the movement of the earth beneath it, plant overgrowth and increasing tourism. At one point Angkor Wat was listed as World Heritage site in danger but has since upgraded from that status through extensive restoration projects.