The legendary limestone hill dominates Athens and offers fabulous views of the whole city. There's an open-air amphitheater and a great restaurant serving seafood, located at the top. It's quite a steep climb, but worth the effort. Funicular also goes to the hill if you don't feel like walking. It leaves approximately every half an hour.
Wikipedia https://en.wikipedia.org/wiki/Mount_Lycabettus
Information on Athens Info Guide Website http://www.athensinfoguide.com/wtslykavittos.htm
Address (Unnamed Road), Αθήνα 10676, Greece
Coordinates 37°58'54.732" N 23°44'35.659" E