Sunday day trip from Athens to the Vouraikos gorge, the roughly 20 km gorge between Mount Chelmos and Mount Panachaiko, inside the Chelmos-Vouraikos National Park, part of a UNESCO Global Geopark. The hike follows the line of the historic Odontotos rack railway (running since 1896 between Diakopto and Kalavryta), with part of the route on the E4 trail, past dense vegetation, running water, waterfalls, caves and rock formations. One-way traverse, 14.5 km, 670 m of descent (mostly downhill), about 4.5 hours with stops; organizer grade 2/5. The coach waits at the end of the route. The organizer does not name the start and finish points: given the distance and the descent, the route most likely runs from the Zachlorou area down to Diakopto, so the map points (Zachlorou station, Diakopto station) are approximate. Coach departures: Chalandri metro station 07:00, Doukissis Plakentias metro station 07:10. Mountain leader: Sotirios Manikas, certified in first aid. Bring a backpack, water, snacks, hiking boots, poles, a rain jacket, a personal first-aid kit, and spare clothes and shoes for the return (left on the coach). Participation is under each hiker's own responsibility (Tyrol Declaration); the leader may change or cancel the route for safety; photos from the hike may be posted online. Participants must be in good health and tell the leader about allergies or illnesses, follow the leader's instructions, keep the group's pace and visual contact, and neither overtake the leader nor fall behind the sweeper. Price not announced in the organizer's text. Bookings by phone with Sotiris Manikas, 6974999545, by email at drapetesthspolis@gmail.com, or by Facebook message to the page «Πεζοπορικός Όμιλος Χαλανδρίου Δραπέτες της πόλης».