This used to be an upper class hotel back in the '60s and the early '70s. State owned, it was built on Parnitha mountain, at 1050m altitude and it was abandoned in the late '70s. Today is deserted, looted and almost in ruins. The inside is spooky. Totally destroyed, burned furniture and carpets, broken floors. As of today, there are no plans for its future.
This interesting structure, where it used to be the covered lounge of the hotel, has the tree's roots built in this cylinder all the way down to the ground.
See the place in Wikimapia