Persepolis (About this sound listen (help·info) Old Persian: 𐎱𐎠𐎼𐎿 Pārsa, Modern Persian: تخت جمشید/پارسه, Takht-e Jamshid or Chehel Minar, UniPers: Taxte Jamڑid) was the ceremonial capital of the Persian Empire during the Achaemenid dynasty (ca. 550-330 BCE). Persepolis is situated 70 km northeast of the modern city of Shiraz in the Fars Province of modern Iran. In contemporary Persian, the site is known as Takht-e Jamshid (Throne of Jamshid) and Parseh. The earliest remains of Persepolis date from around 515 BCE. To the ancient Persians, the city was known as Pārsa, which means "The City of Persians". Persepolis is the Greek interpretation of the name ذفٌَçٍ ًüëéٍ (Persēs polis: "Persian city").
Location of Persepolis
Archaeological evidence shows that the earliest remains of Persepolis date from around 515 BC. André Godard, the French archaeologist who excavated Persepolis in the early 1930s, believed that Cyrus the Great chose the site of Persepolis, but that Darius the Great built the terrace and the great palaces.
Darius ordered the construction of the Apadana Palace and the Council Hall (the Tripylon or three-gated hall), the main imperial Treasury and its surroundings. These were completed during the reign of his son, King Xerxes the Great. Further construction of the buildings on the terrace continued until the downfall of the Achaemenid dynasty.
The location of Persepolis can be found on Google Maps here.
Plan of Persepolis
The first European to visit the ruins of Persepolis was Antonio de Gouveia from Portugal, who wrote about cuneiform inscriptions following his visit in 1602. His first written report on Persia, the Jornada, was published in 1606.
The first scientific excavations at Persepolis were carried out by Ernst Herzfeld and Erich F Schmidt representing the Oriental Institute of the University of Chicago. They conducted excavations for eight seasons beginning in 1930 and included other nearby sites.    
Herzfeld believed the reasons behind the construction of Persepolis were the need for a majestic atmosphere, a symbol for their empire, and to celebrate special events, especially the “Nowruz”. For historical reasons, Persepolis was built where the Achaemenid Dynasty was founded, although it was not the center of the empire at that time.
Persepolitan architecture is noted for its use of wooden columns. Architects resorted to stone only when the largest cedars of Lebanon or teak trees of India did not fulfill the required sizes. Column bases and capitals were made of stone, even on wooden shafts, but the existence of wooden capitals is probable.
The buildings at Persepolis include three general groupings: military quarters, the treasury, and the reception halls and occasional houses for the King. Noted structures include the Great Stairway, the Gate of Nations (Xerxes the Great), the Apadana Palace of Darius, the Hall of a Hundred Columns, the Tripylon Hall and Tachara Palace of Darius, the Hadish Palace of Xerxes, the palace of Artaxerxes III, the Imperial Treasury, the Royal Stables and the Chariot House.
Representation palace of Darius at Persepolis
Persepolis is near the small river Pulwar, which flows into the river Kur (Kyrus). The site includes a 125,000 square meter terrace, partly artificially constructed and partly cut out of a mountain, with its east side leaning on Kuh-e Rahmet ("the Mountain of Mercy"). The other three sides are formed by retaining walls, which vary in height with the slope of the ground. From 5 to 13 meters on the west side a double stair, gently slopes to the top. To create the level terrace, depressions were filled with soil and heavy rocks, which were joined together with metal clips.
Around 518 BC, construction of a broad stairway was begun. The stairway was planned to be the main entrance to the terrace 20 meters above the ground. The dual stairway, known as the Persepolitan stairway, was built in symmetrically on the western side of the Great Wall. The 111 steps were 6.9 meters wide with treads of 31 centimetres and rises of 10 centimetres. Originally, the steps were believed to have been constructed to allow for nobles and royalty to ascend by horseback. New theories suggest that the shallow risers allowed visiting dignitaries to maintain a regal appearance while ascending. The top of the stairways led to a small yard in the north-eastern side of the terrace, opposite the Gate of Nations.
Grey limestone was the main building material used in Persepolis. After natural rock had been levelled and the depressions filled in, the terrace was prepared. Major tunnels for sewage were dug underground through the rock. A large elevated water storage tank was carved at the eastern foot of the mountain. Professor Olmstead suggested the cistern was constructed at the same time that construction of the towers began.
The uneven plan of the foundation of the terrace acted like a castle whose angled walls enabled its defenders to target any section of the external front. Diodorus writes that Persepolis had three walls with ramparts, which all had towers to provide protection space for the defense personnel. The first wall was 7 meters tall, the second, 14 meters and the third wall, which covered all four sides, was 27 meters in height, though no presence of the wall exists in modern times.
Ruins of a number of colossal buildings exist on the terrace. All are constructed of dark-grey marble. Fifteen of their pillars stand intact. Three more pillars have been re-erected since 1970. Several of the buildings were never finished. F. Stolze has shown that some of the mason's rubbish remains. These ruins, for which the name Chehel minar ("the forty columns or minarets") can be traced back to the 13th century, are now known as Takht-e Jamshid - تخت جمشید ("the throne of Jamshid"). Since the time of Pietro della Valle, it has been beyond dispute that they represent the Persepolis captured and partly destroyed by Alexander the Great.
Behind Takht-e Jamshid are three sepulchres hewn out of the rock in the hillside. The façades, one of which is incomplete, are richly decorated with reliefs. About 13 km NNE, on the opposite side of the Pulwar, rises a perpendicular wall of rock, in which four similar tombs are cut at a considerable height from the bottom of the valley. The modern Persians call this place Naqsh-e Rustam - نقش رستم or Nakshi Rostam ("the picture of Rostam"), from the Sassanian reliefs beneath the opening, which they take to be a representation of the mythical hero Rostam. It may be inferred from the sculptures that the occupants of these seven tombs were kings. An inscription on one of the tombs declares it to be that of Darius Hystaspis, concerning whom Ctesias relates that his grave was in the face of a rock, and could only be reached by the use of ropes. Ctesias mentions further, with regard to a number of Persian kings, either that their remains were brought "to the Persians," or that they died there.
The Gate of All Nations
The Gate of all Nations, referring to subjects of the empire, consisted of a grand hall that was a square of approximately 25 meters (82 feet) in length, with four columns and its entrance on the Western Wall. There were two more doors, one to the south which opened to the Apadana yard and the other opened onto a long road to the east. Pivoting devices found on the inner corners of all the doors indicate that they were two-leafed doors, probably made of wood and covered with sheets of ornate metal.
A pair of Lamassu's, bulls with the head of a bearded man, stands by the western threshold. Another pair, with wings and a Persian head (Gopنt-Shنh), stands by the eastern entrance, to reflect the Empire’s power.
Xerxes' name was written in three languages and carved on the entrances, informing everyone that he ordered it to be built.
Darius the Great built the greatest and most glorious palace at Persepolis in the western side. This palace was called the Apadana (the root name for modern "ayvan"). The King of Kings used it for official audiences. The work began in 515 BC. His son Xerxes I completed it 30 years later. The palace had a grand hall in the shape of a square, each side 60 m long with seventy-two columns, thirteen of which still stand on the enormous platform. Each column is 19 m high with a square Taurus and plinth. The columns carried the weight of the vast and heavy ceiling. The tops of the columns were made from animal sculptures such as two headed bulls, lions and eagles. The columns were joined to each other with the help of oak and cedar beams, which were brought from Lebanon. The walls were covered with a layer of mud and stucco to a depth of 5 cm, which was used for bonding, and then covered with the greenish stucco which is found throughout the palaces. At the western, northern and eastern sides of the palace there was a rectangular veranda which had twelve columns in two rows of six. At the south of the grand hall a series of rooms were built for storage. Two grand Persepolitan stairways were built, symmetrical to each other and connected to the stone foundations. To protect the roof from erosion, vertical drains were built through the brick walls. In the four corners of Apadana, facing outwards, four towers were built.
The walls were tiled and decorated with pictures of lions, bulls, and flowers. Darius ordered his name and the details of his empire to be written in gold and silver on plates, which were placed in covered stone boxes in the foundations under the Four Corners of the palace. Two Persepolitan style symmetrical stairways were built on the northern and eastern sides of Apadana to compensate for a difference in level. Two other stairways stood in the middle of the building. The external front views of the palace were embossed with pictures of the Immortals, the Kings' elite guards. The northern stairway was completed during Darius' reign, but the other stairway was completed much later