Imagine a story about a magical castle and write the opening sentence.
Once upon a time, hidden deep within the lush green forests, stood a majestic castle that glimmered in the sunlight with an ethereal aura, as if it were spun from magic itself.
Complete the following task based on the instruction and optional input provided.### Instruction:
Imagine a story about a magical castle and write the opening sentence.

### Output:
Once upon a time, hidden deep within the lush green forests, stood a majestic castle that glimmered in the sunlight with an ethereal aura, as if it were spun from magic itself.