The Colosseum is damaged because of natural disasters, in particular, earthquakes. There have also been people throughout the ages who have broken away pieces of this great structure to keep as souvenirs.
The Colosseum was built between 70 A.D. and 72 A.D. and took about a decade to build. It has been the home to numerous events such as executions, reenactments, and dramas.
This structure was built incredibly well as it has stood the test of time despite the many earthquakes that have struck in the area.
In addition to natural disasters, it is simply old and had been put through years of weathering so damage is to be expected.
The Colosseum in Rome has been damaged both by natural disaster and simply by the fact that it is so old.
The building was started around 70 AD and completely finished by 80 AD, so it is only a few decades less than two thousand years old. This of course explains a lot of why it is damaged.
Another cause of a great deal of damage was an earthquake in medieval times. The earthquake happened in 1349 and severely damaged one side of the building since it was on less stable ground.
The damage to the Colosseum in Rome is attributed to several factors including natural disasters. The structure survived fires, lightning and even some of the earthquakes in the 5th century. This was until massive earthquakes in 847 and 1231 brought down some of the stones leading to the fall of the southern wall.
The decorations and precious stones used in parts of the Colosseum, such as the statues and floor were pillaged and reused in other structures. It is stated that the steps of St. Peters in Rome were built from stones obtained from the Colosseum.
Metal clamps that held the floors and stones together were also looted and used in making weapons during the wars of the middle Ages. In fact the holes that can now be seen between the stones are as a result of the removal of the metal clamps.
Subsequent chipping away of the walls by tourists for souvenirs has also led to further deterioration of this magnificent structure.
There are three reasons why the Colosseum is damaged.
First, it was built very long ago under the leadership of the Flavians. It was started around 70-72 and was completed nearly 10 years later. So, from a historical point of view, there is natural wear and tear. The natural elements for the last two thousand years damaged it. We cannot underestimate this point.
Second, there were also other natural disasters such as lightning strikes and earthquakes.
Finally, because the Roman Empire fell and people were building new projects, often times people used ancient sites as quarries. This is what happened to the Colosseum. Many famous buildings were built from the Colosseum. For example, the cathedrals of St. Peter and St. John Lateran were partially built from the Colosseum. Also defense fortification around the Tiber were also built from the remains of the Colosseum.