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The French village of Allouville-Bellefosse is famous for the Chêne Chapelle (Oak Chapel), which is literally a chapel built into an oak tree. The amazing architecture consists of a wooden staircase spiraling around the ancient tree, leading up to a couple of chambers. These rooms have always been used as places of worship by the village locals.

The tree is known to have been growing as far back as the thirteenth century, during the rule of Louis IX.  It is also known to have survived the Hundred Years War against the English, the Black Death, the Reformation, and Napoleon’s rule. Local folklore dates it a 1,000 years old, when it is said that the acorn took root. However, tree experts say it could only be around 800 years old.

The oak has seen its share of tough times. In the late 1600s, when it was around 500 years old, it was struck by lightning one stormy night.  Although a hollow was burnt right into the centre of the tree, new branches and leaves continued to grow. In view of the miracle that had occurred, the tree was pegged as a sort of holy spot, deserving of a pilgrimage. The staircase and chapel were built soon after. (via)