Nearly half of the Valles Marineris canyon system is visible here. The entire system extends over 4000 km (2490 mi), covering about one fifth the circumference of Mars. Some parts of the canyon run as deep as 7 km (4 mi) and as wide as 200 km (125 mi). Compared to Valles Marineris, the Grand Canyon on Earth seems quite small at 446 km (277 mi) long, 30 km (18 mi) wide and 1.6 km (1 mi) deep.

Olympus Mons is the largest volcano on Mars. This shield volcano, similar to volcanoes in Hawaii, measures 624 km (374 mi) in diameter by 25 km (16 mi) high. It is 100 times larger than Mauna Loa on Earth. Located on the Tharsis Plateau near the equator, Olympus Mons is bordered by an escarpment. The caldera in the center is 80 km (50 mi) wide and contains multiple circular, overlapping collapse craters created by different volcanic events. The radial features on the slopes of the volcano were formed by overflowing lava and debris.

This mosaic of Viking Orbiter frames shows the South Polar Cap of Mars. The polar cap is composed of water and carbon dioxide ice. The ice appears reddish due to dust that has been incorporated into the cap.

Visible in the lower right corner of the image is the lander's footpad. The shroud that protected the soil collector head during the lander's descent lies a short distance from the footpad. The rounded rock in the center foreground is about 20 cm (8 in) wide. The angular rock to the left and further back is about 1.5 m (5 ft) across. Notice the two trenches dug in the regolith by the sampler arm. The gently sloping troughs between the artificial trenches and the angular rock, which cut from the middle left to the lower right corner, are natural surface features.

Among the images obtained by the Viking mission to Mars in 1976 are some that show peculiarly shaped surface features that are inconsistent with the regional geology and with surrounding landforms.

The first of these unusual features to be noticed was a 2 km long knob that resembled a human face staring straight up from the surface. The Face was found in the northern hemisphere of Mars at the boundary between the basin of Acidalia Planitia and the higher ground of Cydonia Mensae. The object's resemblance to a face was noticed by NASA personnel at the Jet Propulsion Laboratory (JPL), who briefly displayed it at a press conference. NASA officially dismissed the Face as a trick of light and shadow. The Face was rediscovered by Vincent DiPietro and Gregory Molenaar, computer scientists working at the Goddard Space Flight Center who unexpectedly found it while working with the Viking imagery. They later found another image of the Face that had been taken under different lighting conditions. Computer enhancement of these images revealed bilateral symmetry, detail resembling eyes, a nose, and a mouth, and persistence of this detail under two different sun angles. Their work was largely ignored by the planetary sciences community, and was published independently as a monograph (DiPietro and Molenaar). Subsequent work by Dr. Mark Carlotto using single-image shape from shading techniques demonstrate that the Face is not a trick of light and shadow or the result of variations in surface albedo.

Richard Hoagland, seeing the work of DiPietro and Molenaar, began investigating the imagery and discovered the presence of a cluster of polyhedral objects, later named the "City", that have a rectilinear arrangement and a major axis aimed directly at the Face. The Face's axis of symmetry is itself perpendicular to the City's major axis. Hoagland later demonstrated that a square arrangement of objects in the center of the City, termed the "City Square", marks the exact midpoint along the City's major axis, and would have served as an excellent vantage point for a sightline to the Face.