Εκεί ψηλά στον Υμηττό υπάρχει κάποιο μυστικό.. (There on the heights of Hymettus there is a secret..) Manos Hadjidakis song

Hymettus view from the east (Source)

Hymettus, also Hymettos or Imittos (Gr. Υμηττός, phonetic spelling Imitós) is a mountain range in Athens Area, East Central Greece. It is also colloquially known as Trellos or Trellovouno (crazy mountain), probably because of its propensity to change colors under shifting sunlight. The height is 1,026 m and the length is 16 km (10 mi) between Athens and the Saronic Gulf and 6 to 7 km from east to west. It ws noted for its thyme honey. Marble has been quarried since antiquity. The neighboring communities that surround the mountain are Athens, Zografou, Kaisariani, Vyron, Ilissium, Helioupoli, Elliniko, Glyfada, Voula and Vouliagmeni in the west, Varkiza, Vári, Markopoulo and Paeania to its east, and Papagou, Agia Paraskevi, Gerakas and Glyka Nera. Most of the forest is in the north, and much of the mountain is rocky, deforested, grassy and made out of limestone.

Major campuses of the Athens University and the National Technical University (collectively called "University Town") are located on the west-facing slope, between the newly-built "Hymettus Peripheral", a ring road connencted with the Attiki Odos freeway, and the Athens urban sprawl. A transmitter park for all major TV and radio stations is located at the top of the mountain. Urban housing almost surrounds the entire mountain range.

Almost all of Athens, eastern suburbs, and the new airport can be seen from the mountaintop along with a few mountains of Parnitha to its northwest, Penteli to its north, and Aegaleo to its west.

Strabo

Of the mountains, those which are most famous are Hymettus, Brilessus, and Lycabettus; and also Parnes and Corydallus. Near the city are most excellent quarries of marble, the Hymettian and Pentelic. Hymettus also produces the best honey. The silver mines in Attica were originally valuable, but now they have failed. Moreover, those who worked them, when the mining yielded only meager returns, melted again the old refuse, or dross, and were still able to extract from it pure silver, since the workmen of earlier times had been unskillful in heating the ore in furnaces. But though the Attic honey is the best in the world, that in the country of the silver mines is said to be much the best of all, the kind which is called acapniston *, from the mode of its preparation.
* withouse using smoke