Hellenistic stoa with lateral projecting wings with tetrastyle facades (end of 3rd c. BC). The stoa is 87 m long and consists of 42 columns in all. The wall of the stoa was not all one, but wasinterrupred in the middle for a space of ten columns so that the staircase of the Propylaea could be seen. The space in front of the stoa was extended at a later date and two underground cisterns were constructed to collect the rainwater from the stoa roof and the staircase of the propylaea. The square so formed was supported on arched constructions which are still visible (1st c. BC).