The walk up Philopappos is a bit of a trek up the small rocky path through the olive and cypress trees, it seems as if you are in the country side, not in the centre of Athens.
On your way up Philopappos you will pass a small cave which is supposed to be the prison of Socrates, but there is no proof of this, and it is much more likely to have been imprisoned in the state prison in the ancient Agora.
The hill was known as the hill of Muses in ancient times, but nowadays it is named after the concave monument of Philopappos on the summit. The monument is in honour of Caius Julius Antiochus Philoppapus who was a popular Roman Consul of Athens. The monument is 12m high and built between AD 114-16.
The hill has always had an important role in the history of Athens, especially for defending the city. The first fort on the hill was built the General Demetrios Poliorketes in 294BC as the hill over looks the Piraeus road and has been used for the same thing many times since.
It is often believed that the Parthenon and the Acropolis was bombarded by cannon fire in 1687 by the Venetian Francesco Morosini from Philopappos hill due to the Turkish using the Acropolis as an armoury leading to much of the present damage including the destruction of the roof of the Parthenon. But in actual fact the Acropolis was bombarded by mortar fire much further down on the hill closer to the Acropolis.