The Ancient Cliff House (Guyaju), 'the biggest maze of China', is an ancient dwelling place on the side of a cliff. There are over a 100 rooms connected by stone steps, stone stairs and plank roads. The houses vary in size, from over 20 square meters to 3-4 square meters. Some are interlinked perpendicularly, some interconnected horizontally. Some have one room, others have 2-3 connecting rooms. Stone steps, and stone ladders are used to connect the entire cliff house.
Coober Pedy is an Underground City in South Australia mainly inhabited by workers at the nearby opal fields, which are the largest in the world. The residences are underground to escape the scorching heat. A few years ago, a man fixing the stairway to his home found over 100,000 dollars worth of opal.