Alfava Metraxis
Alfava Metraxis[source needed] was a planet home to the Aplans, but in the far future was terraformed and colonised by Human settlers.
The Aplans left notable landmarks on the planet, including the Aplan Mortaria, sometimes known as 'Mazes of the Dead'. These were large subterranean labyrinths with tombs in the walls, adorned with statues of the dead. The Mazes have six levels, to represent the ascent of the soul.
The civilisation of the Aplans was noted to have mysteriously come to an abrupt end in the 47th century. This was revealed to have been caused by the Weeping Angels, which infested the dark underground Mazes, well hidden amid the numerous statues. Having hunted the Aplans to extinction, the Angel colony lacked any further energy source and over the centuries, the energy-deprived Angels began to degrade and lose their form. By the time human settlers reached the planet, the Angels within the mazes were too weak to venture out to attack.
In the 51st century, a lone, healthy Angel feigned dormancy and allowed itself to be captured to ensure that it was placed on the Byzantium, a large spaceship with a temporal core. When the ship passed near to Alfava Metraxis, the Angel presumably hunted down all the crew, and allowed the ship to crash into one of the Mortaria. The Angels in hibernation within the maze were then able begin rejuvenation using the power from the ship.
After the crash of the Byzantium, the Doctor, Amy Pond and River Song, with a collection of clerics, landed on Alfava Metraxis with the intention of tracking down and capturing the Weeping Angel that had been contained in its vault. (DW: The Time of Angels)