A propylaea means an monumental gateway in ancient Greek architecture. Entrance into the Acropolis was controlled by the Propylaea. Though it was not built as a fortified structure, it was important that people not ritually clean be denied access to the sanctuary. It was one of several public works commissioned by the Athenian leader Pericles in order to rebuild the Acropolis hill at the conclusion of the Persian Wars. Pericles appointed his friend Phidias as the supervisor and lead architect of this massive project, which Pericles allegedly financed with funds appropriated from the treasury of the Delian League. According to Plutarch, the Propylaea was designed by the architect Mnesicles, about whom nothing else is known. Construction began in 437 BC and was terminated in 432, when the building was still unfinished.
The Propylaea survived intact through the Greek, Roman and Byzantine periods. During the period of the Duchy of Athens, it served as the palace of the Acciaioli family, who ruled the duchy from 1388 to 1458. It was severely damaged by an explosion of a powder magazine in 1656, foreshadowing the even more grievous damage to the Parthenon from a similar cause in 1687. A Frankish tower, erected on the south wing, was pulled down in 1874.
The core is the central building, which presents a standard six-columned Doric façade both on the West to those entering the Acropolis and on the east to those departing. The columns echo the proportions of the columns of the Parthenon.
The Greek Revival Brandenburg Gate of Berlin and the Propylaea in Munich both evoke the central portion of the Athens propylaea.References:
The Naveta d"Es Tudons is the most remarkable megalithic chamber tomb in the Balearic island of Menorca.
In Menorca and Majorca there are several dozen habitational and funerary naveta complexes, some of which similarly comprise two storeys. Navetas are chronologically pre-Talaiotic constructions.
The Naveta d"Es Tudons served as collective ossuary between 1200 and 750 BC. The lower chamber was for stashing the disarticulated bones of the dead after the flesh had been removed while the upper chamber was probably used for the drying of recently placed corpses. Radiocarbon dating of the bones found in the different funerary navetas in Menorca indicate a usage period between about 1130-820 BC, but the navetas like the Naveta d"Es Tudons are probably older.
The shape of the Naveta d"Es Tudons is that of a boat upside down, with the stern as its trapezoidal façade and the bow as its rounded apse. Its groundplan is an elongated semicircle. Externally, the edifice is 14.5 m long by 6.5 m wide and 4.55 m high but it would originally have been 6 m high.
The front, side walls and apse of the edifice consist of successive horizontal corbelled courses of huge rectangular or square limestone blocks dressed with a hammer and fitted together without mortar, with an all-round foundation course of blocks of even greater size laid on edge.