The Pantheon is an old structure – not nearly as aged as the Pyramids, but definitely older than most world wide. It is a dome structure made from pozzalan concrete, first commissioned by Marcus Agrippa in the first century, rebuilt in it’s current form by Hadrian around 126.
It has had continuous use through out its lifespan, which is probably why it is one of the best, if not the best preserved Roman Structures. Perhaps the most striking fact is that almost 2000 years after its construction, it’s structure is still the largest unreinforced concrete dome in the world.
Most known for the oculus in the top center of the dome that allows for natural light, the Pantheon certainly had auspicious beginnings. It’s debated whether this was a temple private to Marcus or if it were open to the public, some claim that this is the original structure set down by Marcus, while there is compelling evidence to suggest that only the facade remains from the original. What is known is that the original building was significantly damaged in 80. It was rebuilt and destroyed in 110; the current building was started under Trajan and completed under Hadrian.
The building was given over to the Catholic Church in the 7th century and if not for this, the building probably would be only a memory, as it was consecrated as a church it avoided abandonment like the majority of the other Roman structures. Over time the exterior has been savaged; some of the column capitals reside in the British Museum. The external marble is virtually all gone. While there have been changes to the exterior, the interior has seen extensive care and restoration.
i have not had the opportunity to visit this place – but i hope to get to go there one day and have my own memories.