The walls and gates of ancient Piraeus. Themistocles in 493 BC started to build the fortification around Piraeus. The two main gates of the fortification are at the entrance to the modern town on Triakostou Tetartou Syntagmatos street. The Asty Gate is the westernmost gate enclosed by Pylis-Omiridou Skylitsi and Kolokotroni streets. The main carriage road to Athens passed through the Asty Gate. The ruins of the fortifications are well preserved nowadays.

The Long Walls and the Middle Gate. The purpose of the construction of the Long Walls was to link Athens with its harbor. The Long Walls (northern, Phaleric, and the middle or southern wall) created a secure corridor between Athens and Piraeus for the population of Attica during the Peloponnesian war. The Middle Gate near Asty Gate is very similar to the Dipylon Gate in Athens but smaller. It was constructed for traffic using the corridor of the Long Walls.

The Eetioneia Gate is situated at the north side of the main harbor, Kantharos, at Drapetsona area. The fortress of Eetioneia was constructed in order to control the harbor. Two sections of wall start from this gate. The first runs east towards the harbor. The second runs towards the outer harbor. Two round strong towers of the Hellenistic era flanked the gate. The wall is protected by a deep moat dug into the rock.

The coastal section of the fortification. It was built by Conon in 394 BC and is today preserved for a length of 2.5 km along the Piraeus Peninsula. Many of the towers of the wall are preserved nowadays.