The archaeological site of ancient Chaleion at Galaxidi is most interesting for the preserved sections of the late fourth century fortification wall. Built of large rectangular blocks in isodomic masonry, on the rocky peninsula between the two ports, the wall controled the sea routes of the Corinthian gulf and the important road connecting the Peloponnese and central Greece, thus making Chaleion the safest port in the Corinthian gulf. Part of the wall of the south port was demolished in 1830, during the construction of the dock; the ancient blocks used for the dock are still visible today. Chaleion's cemeteries and the grave gifts that they contained provide a wealth of information on the life of the city's inhabitants. Two natural caverns with rock-hewn sarcophagi used as burial chambers during the Roman and Early Christian periods are also noteworthy.