The arch of Hadrian is a monumental arch similar to, in some respects, to a triumphal Roman arch. It is located on an ancient street that connects the center of Athens, Greece, to the complex of facilities on the eastern side of the city, including the Temple of Zeus Olimpio. It was hypothesized that the arch was built to celebrate the adventus (arrival) of Roman Emperor Hadrian, and to honor him for what he had done for the city at the inauguration of the nearby temple in 131 or 132. It is not certain who commissioned the construction of the bow, even though it was probably the citizens of Athens or another Greek group. On the arch there are two inscriptions, placed in opposite directions, which quote Teseo and Adriano as founders of Athens. While it is clear that the inscription makes honor to Adriano, it is not known whether the reference to the city is to be understood in its entirety or in one part, the new one. The original hypothesis, that is, the arch marking the limit of the ancient wall circle, and hence the division between old and new cities, has been proved to be false by further excavations. The arch is 325 meters south-east of the Acropolis of Athens. The whole monument is made of pentelic marble, ie coming from Mount Pentelikon, The pentelic marble is also used for the Parthenon and other famous structures of Athens, although its quality is very variable. The marble used for the arc is of lower quality than that used for other structures. The arch was constructed without cement and mortar, using only solid marble and clamps to join the stones. It is 18 meters high, 14 meters wide and deep 2.3. Its appearance is completely symmetrical along the front-to-back, and left-right directions. The passage of the bow to the lower level is 6,5 meters wide and is supported by columns enclosed by Corinthian capitals. Similar, but higher, other pillars were placed at the lower level corners. The space between the outer columns and the opening of the arc was filled with square stones with skewed edges to emphasize its appearance. On the other side, the central passage was decorated with a corinthian column over a rectangular raised base protruding from the center of the wall. The lower level is crowned by an ionic architrave with small merlons and a geiser in relief. The upper level of the arc is made up of a series of columns and pillars of Corinth, which divide the space into three rectangular openings. Each of the side openings is surmounted by an Ionic architrave with small bits and a geis in relief, as well as for the lower level. The central opening is flanked by columns with half Corinthian columns that support a triangular relief structure, placed above the merle, the geis, and a smooth joining the two wings. As it was analyzed, architecturally by Stuart and Revett in the mid 18th century, the base of the bow was buried in the land for only one meter. Considering that it has never been protected from burial in its 19 centuries of life, the arc has come to us in extraordinary conditions. Although the columns of the lower level are missing, the arc has been preserved in all its height. In recent decades, air pollution has damaged the monument. You notice an exaggerated discoloration of the stone and a damage to the inscriptions.