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Echo Mesa is a location on Io. It was the site of the Traveler's final terraforming efforts before the Collapse, and centuries later remains imbued with great stores of the Traveler's energy. It has long been held as a sacred site for Guardians, especially Warlocks.
In the final days of the Golden Age, after terraforming much of the Solar System, including Mars, Venus and Mercury, for humanity's benefit, the Traveler moved to the icy, volcanic moon of Io, in Jupiter's orbit. Settling at the foot of Echo Mesa, the Traveler set about transferring some of its energy into the moon to render it hospitable for life, while in the process partially constructing a structure known as the Cradle. Its work was interrupted by the arrival of the Darkness and the onset of the Collapse. The Traveler fled to Earth and made its final stand, leaving Io only partially habitable.
During the City Age, the Guardians came to view Io as a sacred site and conducted many pilgrimages there to revere and study the Traveler's last feat. That ended with the arrival of the Red Legion and the start of the Red War. In the absence of the Guardians' stewardship, Echo Mesa was invaded by the Cabal, who sought to study the reservoir of the Traveler's energy, the Vex, who initiated efforts to make Io another machine world, and even the Taken, who began draining the energy reservoir for their own purposes.
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