In the same neighbourhood may be seen one of the best preserved monuments in Athens. It is an octagonal marble building, called the Tower of the Winds, standing fully 40 feet high, with a diameter of 26 feet. On each of its eight sides there is an emblematic figure, representing the wind which blows in that direction. On the top of the tower there was once a bronze Triton, which pointed to the picture of the wind that was blowing at the time. Under each figure is a sun-dial, and there was also an ingenious system of waterworks within the tower, to show the time in any weather, by night or by day. The tower was erected in the first century B.C. by a Syrian named Andronicus. A little farther east stands a great gate or portico, consisting of four Doric columns, 26 feet high, with a massive architrave and pediment. An inscription on the architrave tells that it was erected in honour of Athena _Archegetis_ (“Foundress Athena”) by the people of Athens, from funds bestowed on them by Julius Cæsar and the Emperor Augustus. It was once supposed to be part of a temple, but excavations have proved that it led into a great market-place, which was surrounded by an Ionic colonnade, and was chiefly used (judging from an inscription found in the neighbourhood) for the sale of olive-oil, the great gift of Athena. In the pediment of the gate there was originally a statue of Lucius, the adopted son of Augustus. His son-in-law Agrippa was also held in honour in Athens; and on the Acropolis a pedestal can still be seen, close to the Propylæa, on which his statue rested, with an inscription in which he is styled a benefactor of the city. On the Museum or Observatory Hill there is a marble structure called the Monument of Philopappus, erected in the beginning of the second century A.D., in honour of a generous Athenian citizen of that name, who was the last hereditary king of Commagene, in Asia Minor. Above the frieze are three niches, two of which contain statues of Philopappus and his grandfather Antiochus Epiphanes, while in the third, on the right, there once stood the figure of Seleucus Nicator, the founder of the dynasty. On the north-east side of the hill there are three rock-hewn chambers, no doubt originally tombs, though they are now called (apparently without any justification) the Prison of Socrates. Among all the Roman emperors Hadrian was the [Illustration: THE PORTICO OF ATHENA ARCHEGETIS AT ATHENS The entrance to the market-place, built in the time of Augustus. On the side of the cliff of the Acropolis we see the caves of Pan and Apollo beneath the north wing of the Propylæa.]