I was born and raised in Bulgaria and when I went back several years ago, I visited the Monastery of Rila. Rila is a mountain high in the Balkans and the monastery is one of the most famous in Bulgaria.
It was originally the area in which St. John of Rila spent his life as a hermit. After his death, a monastery was built in the valley directly below the cave in which he lived. During the years of Ottoman rule, this monastery was a light to the Bulgarian people. It has always been the center of Bulgarian spirituality along with many other monasteries.
The basic complex of the Rila Monastery consists of the main catholicon (church), the residential buildings, and the bell tower. Of the buildings, the bell tower is the only original building that has survived the onslaught of the centuries the rest are from the 19th century. The bell tower was where the monks hid when the Turks came through and burned down the monastery. It is very high and the upper floor is now a museum.
Outside of the monastery via a winding road uphill is the cave where St. John of Rila spent his life. It is approached through steps and on the inside it is completely dark. There is a small hole in the ceiling and it is said that whoever can climb through that hole can have good luck. It is true for all people.
Outside of the hole, is the rock on which St. John of Rila spent many days and nights in vigil. I have seen the imprints of his knees on the rock (although the rock is upright now). The entire mountain seems to have been sanctified by St. John's presence. In the entire area, there a rocks and clefts that are marked with a cross and an image of the saint indicating that he was there. Even the water has a sweet taste and reminds us of the story of Moses and the Israelites in the wilderness.
The monastery museum houses some of the greatest treasures in the monastery. One particular favorite of mine is the blessing cross of Father Raphael. During the nineteenth century, Father Raphael was commissioned by the abbot for an exquisite cross. It took Father Raphael twelve years to complete the cross and it cost him his site because he carved in exquisite detail, scenes from the New Testament. To see the scenes in all of their details, you need to get a magnifying glass and look through the bullet proof glass in which the cross is protected.
If you ever go to the monastery, the monks sometimes take out the relics of St. John of Rila for veneration. I don't know how often this happens, but it happened while I was there. I was allowed to venerate one of the hands of St. John of Rila and it is a true blessing.
I hope that I have given you a little overview. I am sure that there is an official Rila site somewhere out there on the internet.
God bless all of you.
PS: St. John, by the way, was the patron saint of St. John of Kronstadt (a great saint of 19th century Russia and particular favorite of mine). The chapel in which St. John's relics were originally buried was dedicated to St. John of Rila.