The ancient theater of Zea is located outside the Archaeological Museum of Piraeus. The theater has the typical tripartite organization of a Hellenistic theater, i.e. auditorium, orchestra and stage building. The theater was built in Macedonian times (beginning of the 3rd century BC) and had as its model the great Athenian Theater of Dionysus. Its auditorium was partly founded on the natural rock, while in its upper part, where there was no natural rock, the seats were based on an artificial stone foundation, which was covered with soil.

A letter dated in 1672 informs us about the merchandise warehouse and the customs officer at the port. The warehouse and inn, the caravanserai, a fire tower, a settlement further from the port, the village at Keratsini and the church of Agios Nikolaos, were the only traces of human presence from the port to the western shores of Piraeus. Chateaubriand in Itinéraire de Paris à Jérusalem of 1806 mentions that the port had the monastery of Agios Spyridon, a warehouse and the customs office. The customs office, the so-called “Dogana” (from the French word Douane), was located in today’s Karaiskaki square, while in 1835 it was moved to Agios Nikolaos. In this particular period, there are only two figures in the port, the only inhabitants of the coast along with the monks of the monastery. One of them was Joseph Cayrac, a merchant from Marseilles, who bought around 1750 a building with warehouses and gardens in the port. The other was Gaspari, who built a warehouse next to Kayrac’s building. We come across them in 1770 and 1786 welcoming foreigners and trading oils together.

The Stock Exchange building, also known as the “Clock” of Piraeus, was erected between 1869-73 in the port, opposite the church of Agia Triada, to house the country’s first commodity exchange. It was the symbol of Piraeus. Its architectural study was realized by the city engineer Gerasimos Metaxas. On the ground floor there was a large hall, where transactions were made and deals were concluded. The offices were on the first floor. In the tower of the building, the then Mayor of Piraeus, Dimitris Moutzopoulos, placed the “Clock of the City”. The number of documents in the files of the Piraeus Municipality Archive of the period 1868-1905 are sources of important information. The stock exchange, however, according to the testimonies, only operated for one year. It hosted the city’s Commercial Club for many years, and on its premises balls and charity events were thrown. Also, since 1874, the Mavrokordatos library was housed there. Since 1880 the ground floor functioned as a coffee shop, while later on its floors the municipal services of the city were installed. The building was demolished in 1968, by order of the then Mayor Aristidis Skylitsis.

The half-preserved residence of the flour manufacturer Panagiotis Patsiadis, the Patsiadis Residence, is the only remaining example of Ernesto Ziller’s architectural style in the area of ​​Alexandras Square, where the famous “Mansion Quarter” or “Ziller Quarter” used to be. It consisted of two houses, the construction of which was allegedly completed during the period 1894-1895. The first of the two was demolished around the mid-70s, and a high-rise apartment building was erected in its place, while the second one, an impressive corner building, is organically integrated into the curved front of the street. It consists of two rectangular wings, perfectly symmetrical with respect to the cylindrical volume of the staircase, which is topped with a characteristic conical roof. The ground floor with the arched openings, which also repeat themselves on the first floor, was intended for commercial exploitation, while the first floor for residency. In the circular sector, which joins the two sections, the reception areas were located, in the eastern wing were the rooms and the sanitary areas, while in the south the dining room and the rest of the ancillary areas. Today the surviving building remains closed.

After 1955, a significant effort was made for the development and modernization of the port. Maritime traffic increased during those years, so it was deemed necessary to design new studies and plans that would not only aim at the sea front and ships, but also land areas and merchandise. The above project was undertaken by the civil engineer Dimosthenis Pippas (1906-87), professor at the “Port Works” chair of the NTUA (1933-71). Thus, the necessary land surfaces were created and the maneuvering surfaces in the port of Alon were enlarged. The platforms of the four quays I, II, III, IV of the two triangular quays of V. Konstantinou and Agiou Nikolaou were developed. At the same time, along with the construction of the marine port works (platforms), additional infrastructure works (sheds, warehouses, mechanical equipment, etc.) began to be carried out, with the aim of better exploiting the port. By the end of this period the port had quays of approximately 18,000 m in length. Then began a phase of development and expansion for the port.