There are many natural occurrences that might puzzle a traveler. One of them is Al Naslaa Rock Formation, located in Tayma oasis, Saudi Arabia. Recent archaeological discoveries show that Tayma has been inhabited since the ancient times.
Al Naslaa is one of the most photogenic petroglyphs in the area. The perfect slit between the two standing stones and the flat faces are completely natural. Note the small pedestals supporting the boulders. How long will they remain balanced here? How did the cut in the middle happen?
Most likely the ground shifted slightly underneath one of the two supports and the rock split. Could be from a volcanic dike of some weaker mineral that solidified there before everything was exhumed. Or, it could be an old pressure crack (you see a parallel crack just to the right of it) that has been pushed/pulled apart some. Or, it could be an old (minor) fault line, since fault motion often creates a zone of weakened rock that erodes relatively easier than the surrounding rock.
Location: Tayma, Saudi Arabia
– via saudi-archaeology.com