On a quiet stretch of US Highway 101 in Mendocino County, Northern California, a giant redwood tree has been doubling as a house for over a century. The World Famous Tree House in Piercy stands over 250 feet tall, is estimated to be approximately 4,000 years old, and contains a natural hollow at its base measuring roughly 21 by 27 feet across with a ceiling soaring 50 feet above the floor.