The Everfree was a vast forested area with a mighty river splitting the land like a railroad through a mountain. It was dangerous, because of the strange creatures ranging from Manitcores to Cockatrices residing within. The smaller animals, had to scurry from tree to tree to avoid being something else lunch. It was a vicious fight for life, but it was the nature of life itself.
Nopony expected anypony within their right minds to be able to live too far inside the forest, with the exception of Zecora, let alone a complete civilization. It was a civilization that many had thought a myth, as it had disappeared far before the Crystal Empire. It was gone before the age of the Princesses. It was even gone before the times of Discord. It was the late great Empire of the Horses.
special thanks to SolarEclipse912 for editing