Echus Overlook was a city built in the 2030s inside one of the cliffs of Echus Chasma, formed by ancient aquifer outbreaks.

When Sax Russell was appointed chief scientist of the terraforming effort by UNOMA he used the finance to build a terraforming headquarters at Echus. Built on a 3 kilometer-tall cliff and made of some 400 stories, Echus Overlook offered a mgnificent view. Russell gathered a team of physicists, chemists and biologists in Echus to work on all means possible that would contribute to terraforming and as such Echus was a key place in shaping the Martian industry of the early years. Nuclear power plants released heat; moholes were dug; greenhouse gases were manufactured and released. One particular and very effective gas mixture created at Echus was given the nickname "Russell cocktail" by the science team.

The city came to occupy the entire height of the cliff, with Echus Overlook at its top and Echus Underlook below. After the 2061 revolution, terraforming decisions were taken in multiple places across the planet and Echus was used as a launchpad for light airplanes. The Martian underground also had a secret hideout near Echus with an ultralite plane.

Echus was represented at the Pavonis constitutional congress in 2128. Unlike many other of the early settlements like Underhill, it escaped from becoming a dim historical monument because of its cliffs and the winds falling on it: Echus became a flier's paradise.