The summit of Mt. Parnitha (1,413 m [4,635 feet]), Attica's highest mountain, affords splendid views of the plain of Athens. Sadly, large swaths of its protected national park, particularly on the western side, were destroyed in 2007 by wildfires; even today little more than an eighth of the 3,634 hectares lost to fire has been reforested. Yet one unexpected effect benefit to this tragedy has been a boom in wildlife. Recent years have seen a steep increase in the mountain's wild red deer population (now topping 500); these can be spotted on many of the mountain's trails and lookouts, and are profoundly ambivalent about humans, allowing you to get a close look. They are joined by wild boar, Cretan wild goats (set loose from an old wildlife reserve when the 2007 fire struck), and even wolves and jackals attracted by the abundance of prey—though sightings of predators are rare.
In April and May the forest blooms with wildflowers, red poppies, white crocuses, purple irises, and numerous species of orchid. Many Athenians come year-round, especially on Sunday, to enjoy the clean air, mountain bike trails, picnic spots, or just to take the cable car for the views. So famed was the area for its air quality that a tuberculosis sanatorium operated here until the 1960s; next to its burnt-out shell now stands the Park of Souls, an open-air gallery of sculptures in memory of those who were lost. Near the summit also stands the mountain's rather fusty casino, where the cable car finishes. At the time of writing this building was due to relocate, as new laws now allow casinos within the city limits, and its land is set to be returned to the park.
On the southeast side of the mountain is the most unsual sight of all: the abandoned royal summer palace of Tatoi. Its grounds are free to wander since royalty was abolished here in the 1970s, though legal wrangling over what to do with the estate has meant its buildings here have been sadly neglected and are off-limits to visitors. Cycling and walking tours of the park are offered by a number of local operators.