The Watchtower of the Golden Key is the watchtower of the Aether.
It is described as a place of endless mechanisms, machine components made of gold, silver, and glass occupied in some great task unknown and unknowable to the Awakened. The operation of this mechanism creates music, a great chorus of artificial sounds combining into one harmonic whole. It makes a brilliant contrast to the maelstrom going on outside. There, machines scuttle from place to place, engaged in unknowable tasks, and voices whisper to those who tread its halls guiding the Awakened through the great, golden doors of the tower. The beacon is the Eye of Heaven, a great burning eye that is so bright it can be seen from across the dark gulf of the Abyss.