Situated on a rocky hill, about 90 kilometres (56 miles) southwest of Athens, and commanding over the surrounding plain as far as the sea 15 km away, the site of Mycenae covered 30,000 square metres and has always been known throughout history. From 1600 BCE there is evidence of an elite presence on the acropolis, which is evident from the beautiful wall paintings, high quality pottery, shaft graves and an increase in the surrounding settlement with the construction of large Tholos tombs. The first large-scale palace complex was built on three artificial terraces from the 14th century BCE. It consisted of the celebrated Treasury of Atreus, the Tholos Tomb, a monumental circular building with a corbelled roof. The roof had a height of 13.5 m and a diameter of 14.6 m, approached by a long walled and an unroofed corridor. The corridor was 36 m long and 6m wide. The acropolis, surrounded by fortified walls of roughly worked large stone blocks, flood management structures such as damns, roads, Linear B tablets and an increased import of quality potteries evidences that the culture was at its zenith during the period.
The large palace structure was built around a central hall or Megaron, which is typically a Mycenaean palace. Other features include a secondary hall, a workshop complex and many private rooms. Apart from the decorated stonework and frescoes, a monumental entrance known as the Lion Gate added more splendor and grandeur of the complex. The 3 m x 3 m square Lion Gate with an 18-ton lintel topped by two 3 m high heraldic lions and a column altar, is simply amazing.
Probably the first palace was destroyed in the late 13th century by an earthquake and then repaired, rather poorly. Later, a majestic staircase, the North Gate, and a ramp were added to the acropolis. The walls were also extended to include the Perseia spring within the fortifications. It seems that the second Palace was destroyed by fire. In fact, the actual reasons for the demise of Mycenae and the Mycenaean civilization are not very clear. The suggestions include natural disaster, over-population, internal social and political unrest or invasion from foreign tribes.