Penteli is one of the four mountains surrounding the city of Athens. The mountain has several crags offering a variety of sport and traditional climbing on marble. All the crags are abandoned marble quarries of the recent (or, in the case of Spilia Ntaveli, the distant) past. Climbing here has a different, very distinct feel compared to the limestone crags surrounding Athens. The quality of the rock is good, although brittle in places, but most routes have been climbed extensively and are mostly clean.
From the crags described here, Spilia Ntaveli (which means Ntaveli's Cave) offers the hardest routes of the area, most of which are a mix of sport and trad climbing especially on the lower grades, Ntamari and Sympligades are pure sport climbing crags and, finally, West Wall offers trad climbing, with only two of the most difficult routes having being bolted.
Ntaveli's Cave in specific, is worth a visit for its own sake. Apart from being one of the most important and historical crags for the 80's Athenian climbing scene, it also bears a historical significance as it has been verified by archaeologists to be an ancient marble quarry of the 5th century BC, producing the marble with which the Acropolis was built. The 2nd century Nymph Shrine located above the cave and the 11th century chapel still standing on the entrance, both testify on the unceasing significance of the area for the local community through the ages. Stories from the early 20th century locate one of the numerous hideouts of the notorious arch-bandit Ntavelis (hence the name) in the cave vicinity. Nowadays the cave continues to spawn modern folklore and urban legends, being a hotspot for neo-paganists and a field of study for conspiracy theorists.
Due to its many peculiar visitors, theft of hangers from the first bolt of the routes has been observed in the past. Take a moment to check each route before you start climbing for missing bolts.
For the access to the area, leave Attiki Odos on Exit 12, following Pentelis Avenue and heading north-northeast to Mt. Penteli. 4Km later turn left on the traffic light next to Penteli Highschool. Follow the road to Nea Penteli Square and at the end of the square, 900m from Penteli Highschool, turn left. Pass several bus stops (buses 451, 423 and 530) and continue uphill after the bus terminal stop (Agios Silas Square) till the road gets you past the last house of Nea Penteli suburb. Continue on that road as it starts crossing the low pine forest moving in parallel to the mountain towards Kifisia. On the road split, turn right following the sign for Agios Panteleimonas monastery. Continue uphill till the next split where the road goes left to Agios Panteleimonas. Instead, you turn right and after about 1Km leave the asphalt and get on the second dirt road, leaving the asphalt on your left. This is the road leading to Ntamari, West Wall and Ntaveli's Cave. To avoid confusion, keep your eyes open for a rusty damaged sign that marks this point. The sign is not readable any more but its a good mark for recognizing the correct point to leave the asphalt.
To access the Sympligades crag continue for another 1 km after the sign and stop on a characteristic U turn next to a small road shrine. A rock with a black painted spot marks the start of the old damaged dirt road. Park here and continue on foot following the black spots up to the Sympligades crag (10min walk).
Crag Adis is located above Spilia Ntaveli (alt. 800m) and is a very dark place shaped like a big ship.