Curiosity, the robotic Mars Science Laboratory (MSL), was sent on a mission to Mars by NASA on November 26, 2011.  It successfully landed in Gale Crater on August 6, 2012.  It joined Opportunity, MER-B (Mars Exploration Rover – B), a robotic rover active on the planet since 2004. Launched on July 7, 2003, Opportunity landed on Mars' Meridiani Planum on January 25, 2004 at 05:05 Ground UTC (about 13:15 Mars local time), three weeks after its twin Spirit (MER-A), also part of NASA’s Mars Exploration Rover Mission, touched down on the other side of the planet.  Although the overall objectives include investigating Mars' habitability, climate and geology, the rovers have collected a variety of scientific data, some of which has been completely unexpected.

Stereo View #1 — Taken by the navigation camera on the 201 SOL (or Mars day), the images appear to reveal pyramid-like structures not visible from the orbiting Mars Reconnaissance Orbiter.  Stereography has verified what singular images cannot.  

Stereo View #2 — Taken by the navigation cameras on the 318 SOL (or Mars day), the images appear to reveal a mound of rock that is remarkably similar to the Great Sphinx of Giza, with the body of a lion, but a human head.  

Stereo View #3 — Taken by the navigation cameras on the 176 SOL (or Mars day), the images appear to show skeletal formations which possibly reveal intelligence life forms once roamed the planet.  Some researches have speculated that it even appears mining for minerals or oil has taken place at some point in recent geological time.

Stereo View #4 — The source of these images are unclear, but speculation has begun regarding the possibility that a private space exploration team has ventured to Mars prior to NASA’s Mars Exploration Rover Missions and returned with specimens found buried just below the surface of dunes on the planet. Comparative studies show remarkably human-like features.