The alignment of the three Shield Volcanoes that make up the Tharsis Montes is clearly evident in this view.

The three Volcanoes are Ascraeus Mons, Pavonis Mons and Arsia Mons, going from North to South. They are each somewhat smaller than Olympus Mons, varying from about 350 to 450 Km (approx. 210 to 270 miles) in horizontal extent and each rising about 15 Km (approx. 9 miles) above the surrounding Lava Plains.
The Tharsis Montes are located on the crest of a broad uplift of the Martian Crust so that their Summits are at about the same elevation as the Summit of Olympus Mons.
The "Fractures" visible to the South/East of Pavonis Mons, are known as "Noctis Labyrinthus".

This Tharsis Volcanic Province merges with the enormous Valles Marineris Canyon System to the East. The white patches around the lower Flanks of the Volcanoes are thin Clouds that commonly occur near them.

In is interesting to notice that in two (and, as a matter of fact, very distant in time) pictures, the first taken by the NASA - Viking Orbiter 1 and the second one by the ESA - Mars Express Orbiter, a thick emission of fumes appear visible near the Summit Caldera of the Volcano Arsia Mons which, in our opinion (and contrary to common belief), might still be active (even though we should talk, in this case, about a mere Residual Volcanic Activity).

Unfortunately, an "official" and, of course, thorough scientific investigation of the abovementioned (possible) Residual Volcanic Phenomenon has never been made, as far as we know, neither by NASA, nor by ESA Scientists.

This frame has been colorized in Absolute Natural Colors by (such as the colors that a human eye would actually perceive if someone were onboard the NASA - Viking Orbiter 1 and then looked towards Mars), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team.