Greece is a very special country. It is not only a cradle of democracy – the most advanced and human-friendly type of government so far, but also a country where first pilgrimages took place. Some of the spiritual sanctuaries are now ruins and archaeological sites, but hey, there are roads to them and if only one has a wish to walk them, it might be a very historical experience!
One of the most important sanctuaries in the Ancient Greek world was Delphi. It is believed that a great Oracle used to be there and many people walked all over the vast country to get advice from him. It is believed that Apollo – the prophetic God of arts and healing – used to communicate through the Oracle in Delphi.
The temple of Apollo is just outside the Delphi town about 3 hours bus drive from Athens. However, it is possible to reach Delphi on foot from the port town Kirra/ Itea (or vice versa and take a bus back to Delphi) on nowadays included into Europe’s long-distance route E4 trail. This particular part of E4 was an ancient way that pilgrims used to walk up to the Oracle. Stories from people who walked the trail can be found on Carolyn Schott blog and Trip Advisor Forum. Interactive maps can be found on Wikiloc.
Another suggestion for experienced hikers would be doing hikes to the Ancient Greece Gods’ home Mount Olympus and Mount Parnassus where it is believed the Muses used to live. Keep in mind that both mountains are rather difficult to climb and need special preparation and perhaps a guide.
If you feel like continuing to the north of Greece another pilgrimage site to visit is the famous Orthodox Meteora. There are six monasteries in the area and each of them is built on the top of the different rock.
Arrive at Kalambaka with a train or bus from Athens or Thessaloniki (detailed how to get there is on the official Meteora website), and then walk. It is possible to walk to the monasteries on the trails and on the roads; here are some maps on Wikiloc. After visiting the monasteries (mind that each of them is closed on different days, so check opening times before visiting) you can stay overnight at Kastraki village (see accommodation options in the Meteora area) and head back to Kalambaka or see more the next day. Such walk is around ~20 km walk. I found inspiration for Meteora pilgrimage in one of the posts at the Travel Advisor Forum.
Mount Athos is one of the holiest Eastern Orthodox places in Greece. Unfortunately, no women are allowed to come closer than 500 m from the shore of the peninsula and so for the last 1000 years now. So if you are a man and want to visit the monasteries, or even stay there as a pilgrim, see the rules of application.