Many words may be said regarding the Pantheon, but visiting this magnificent sample of Ancient Roman architecture, is something different. Especially if you do it  with an Architect. The construction system of the Pantheon has been   a mystery for   for centuries.  Mystery that only in the nineteenth century was resolved. Even though, still,  many guide books,  some of them  written by archaeologist and   in sale today  in Rome,  are giving    explanations  regarding its engineering,  that most   architects  refused. 

One of those guide books say  “the Pantheon’s“   dome of 43.3 metres width, equal to the height, was built  turning a concrete flow   on a unique slight arch”. ” . This  assertion has been completely rejected by architects and engineers. The firsts studies regarding the Pantheon’s construction system,  were accomplished in 1892 by the Architects Armannini and Beltrami and continued in 1930 by the professor Terenzio. Both studies confirm  that the  spherical cup with a great  oculus on the summit lays on  huge arches  embedded in the huge mass of concrete  of the dome’s    lower section. These    arches that are supported by 8 big pillars of 18 feet width. The entire dome   follows a sequence of different  constructing materials to reduce slightly the  weight. While in the lower concrete   layers are employed  travertine and bricks or tufa,  in the highest are used concrete with pumice stone.