Each year on August 15- otherwise known as 'Dekapentavgoustos'- on the Greek Orthodox calendar, the 'Feast of the Dormition of the Theotokos' is celebrated.

It’s a national and religious holiday that marks the “falling asleep” or “kimisis” of Panagia (Virgin Mary). The feast also commemorates the Assumption of the body of the Theotokos into heaven.
@greekcitytimes Panagia Evangelistria in Tinos #Greece
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Panagia, according to ecclesiastical tradition, was informed of her pending death by an angel three days prior to it happening, and she began to properly prepare. After shutting her eyes, the Apostles carried her deathbed to the Garden of Gethsemane, where she was buried. After three days, the Apostle Thomas went to her tomb and only found her grave clothes.

Over the tomb of Panagia, a large church was built by Agia Eleni. After its destruction, the Byzantine Emperor Marcian (450-457) built a new church, which still exists today.
The first time a celebration in Panagia’s honour seemed to take place was in Jerusalem, on the 13th of August and later was moved to the 15th and named the “day of Mary the Theotokos.” A “kathisma” (central church of a monastery) outside the walls of Jerusalem on the road to Bethlehem is mentioned as being the initial gathering of such celebrations.
The feast of the ‘Dormition of the Theotokos’ is preceded by a fast, which was established in the seventh century. Nowadays, lent for Holy Communion is for fourteen days and begins on August 1st. During the first 15 days of August, most churches also chant during the evening hours (except Sundays).

In Greece this period is referred to as “Summer Pascha” and on August 15- Panagia Evangelistria in Tinos, Panagia Soumela in Mount Vermion and Panagia Ekatontalliani in Paros are known as the most sacred places of religious pilgrimage.
On August 15, at Her sacred funeral, there are chosen hymns that decorate the Service, with words and eulogies delivered by priests and clergymen on the day of Panagia’s memorial. On many islands and mainland villages, an Epitaphion is decorated and paraded in Her honour.
Here is a list of the most visited churches/monasteries around Greece on August 15th- known for their traditional services and festivities dedicated to the ‘Dormition of the Theotokos.’

Tinos- Church of the Megalohari
Mount Vermion- Panagia Soumela
Leros- Kastrovasilissa- Panagia of Kastro
Astypalaia- Panagia Portaitissa
Rhodes- Panagia Kremasti
Paros- Panagia Ekatodapiliani
Lesvos- Panagia ti Vrefokratousa
Nissyros- Panagia Spiliani
Crete- Holy monastery of Kalyviani
Imvros- Panagia Imvrotissa
Halkidiki- Megali Panagia
Goumenissa- Monastery of the Mother of God
Epirus- Molivdoskepasti Monastery
Kefalonia- Panagia of Langouvarda
Andros- Panachrantos Monastery
Karpathos- Assumption of the Virgin
Amorgos- Amorgos Hozoviotissa Monastery
Skiathos- Evangelistria Monastery
Leonida Kynourias- Panagia of Elonas
Mantinea- Episkopiotissa