Echelon Spires are Xel'Naga psionic communication and research stations. In this capacity, they constantly relayed data on the growth and development of all experimental species and worlds. After the destruction of the Xel'Naga, these structures have ceased all communications to and from the homeworld until the events at Bhekar Ro. Once the signal was received, virtually all of the remaining Xel'Naga artifacts became "active" (Halo 2: Installation 05). Special abilities: * Detector * Build Apex Relay