Iranian history represents a rich blend of legend, mythology, recorded fact and living tradition. Several civilizations have risen in various parts of the country at different times, each leaving its own impression on the subsequent development of Iranian history. The oldest known civilization in Iran is that of Elam in the 10th century B.C. and the Assyrians in the 8th century B.C. Other major Iranian civilizations are Media, Achaemenids, Parthians and Sassanians. Unfortunately, most of the landmarks of these civilizations were demolished during the Arab and subsequent Mongol and Tatar invasions. The 16th century Safavids civilizations that has the most lasting number of monuments has inherited from both Persian civilization and its invaders. Many other dynasties and monarchies succeeded the country until the Pahlavi, that was once again demolished by the Islamic Revolution under the leadership of Imam Khomeini, in a way similar to its predecessors. Iran has a long history of almost 7,000 years since the Aryans emigrated to the Iran Heights. Aryans gave their name to this land and called it “land of Aryans” or Iran. Achaemenid appeared in the 550 B.C. was the first unified dynasty and until it was conquered by Alexander of Macedonia (Eskandar e Maghdooni) in 330 B.C., Iran prospered as “The Great Persian Empire” for more than two centuries. Contributions of the Achaemenians to the worlds culture are numerous. Cyrus (Xerxes) The Great (550 B.C.) was the first emperor who conquered Elam and gave Jews freedom. He was also the first one who declared and practiced human rights. In the Great Persia Empire from East China to Libya, many nations were coexisting and all were declared free to pactice their own religion and follow their own traditions and customs. Daryush The Great (500 B.C.) was the first emperor who commited to digging the ancient Suez Channel, joining the Red and Mediteranian sea. There are many landmarks left from the Achaemenian period mostly in Persepolis and Naghshe-rostam near present Shiraz.