Later on, in the first century AD, the Romans began to use concrete in greater use. The architects of Rome used this concrete to make many structures including domes, arches, and vaults. They added bricks to these structures to improve the strength of the building. After adding the bricks, they put on an extra layer of marble for decoration.
One of the biggest improvements that the Romans made in architecture was the invention of the arch. These arches added a great amount of weight to the structure. To help support this weight, the Romans invented a type of building material that is called a keystone block. The force on top of the arch was directed down to this keystone block. Because of the shape of the keystone block, this force was then pushed through the voussoir blocks that formed the top of the arch. The force then went through the impost and the piers, finally ending up at the foundation. This helped support many of Rome's great structures.
One of the most famous Roman buildings is the Pantheon. The dome of the Pantheon spans 142 feet. The portico of the Pantheon is 46 feet high. It is made of granite, and its pillars are of the Corinthian style. The entablature of the Pantheon states a famous inscription stating that the construction was oversaw by Agrippa. The interior of the Pantheon is in the shape of a cylinder. The diameter at the floor of the cylinder is also 142 feet, which is equal to the height of the interior of the cylinder. The top of the cylinder has a hole in the middle, called an oculus. This oculus is 29 feet from one side to the other. The actual dome is made out of rings of concrete. These rings of concrete have less weight as the raise in height. They also become much less thick towards the top. While the bottom rings were 20 feet thick, they become only 4 feet thick at the oculus. In ancient times, the outside walls had colored marble on them.
The pantheon was originally a Roman temple. The only natural light that enters the Pantheon goes through the oculus from the top and through the bronze doors at the bottom. This results in patterns of light that change throughout the day because of the suns movements. The porch of the Pantheon used to face a temple courtyard. The bronze doors are the entrance to the interior cylinder. Another famous Roman building was the Colosseum. The Colosseum was given its name from a 120 foot statue of Nero. Architects were able to build the Colosseum because of the invention of concrete. The concrete allowed the architects to build tunnels that allowed an easy way to get in and out of the Colosseum. This idea was so great that it is still used in many stadiums in present times.
The Colosseum was opened in 80 AD. To celebrate its opening, the Romans had a 100 day celebration. During this celebration, and the many other days that events were held at the Colosseum, the Romans came to view such events as fighting and public celebrations. The Colosseum had a roof that was made out of canvas. It was raised and lowered by a team of Romans. These Romans were known for their skill in rigging ships. The Colosseum was able to hold up to 50,000 people. These people included slave, foreigners, commoners, dignitaries, and numerous others.
Another one of Rome's architectural feats was Trajan's Column. This structure in Rome was ordered to be built by the emperor Trajan.. It was finished in the year 113 AD. The structure of Trajan's Column is about 90 feet high. Its pedestal is about 24 feet high. The column itself is made up of 18 separate pieces, each weighing around 80,000 pounds. The diameter of the cylinder is around 12 feet. There is a platform at the top for viewing, which is accessible from a spiral staircase set inside the shaft.
The relief on the outside of the shaft is a great work of art.It shows two military campaigns that were conducted against Rome's enemy, the Dacians. The top half of the column shows the first military campaign. The bottom half shows the second campaign. Both were successful.
All of these structures are still standing today. They have helped us learn numerous things about the ancient world. Without these structures, the level of learning that occurs today about Rome might not have occurred.