Shots of hexagonal basalt in Iceland (from here):
Below: Eaglehawk Neck, Tasmania:
Below: Candlerock Lounge, Arden
Below: Giant's Causeway, Ireland:
Below: Devil's Postpile, California. First one from here. Similar formations can be found in Yellowstone and Hell's Canyon Idaho.
Below: Pancake Rocks, South Island, New Zealand (image credit your awesome blogger).
Below, salt, Salar de Uyuni salt flats in Bolivia. Death Valley's Badwater Flat shows a similar pattern. I used to think this was a macroscale manifestation of the arrangement of salt and water atoms, but it's reproduced in a number of media and is actually the result of convection physics (photo below from Jon Chui's blog, check out that link!)
Below, some rocks and shadows on Mars. Come on people, grow up. There's actually a book on this one (no I won't give the guy's sales a boost by linking to the Amazon page.)* And anyway, the bottom one is what it really looks like, after we took more and better pictures of it a few years later. Spend some time on Google maps satellite view looking at various non-face-having Earth mountains for comparison.
Russian "Megaliths". This was announced maybe a year ago with much fanfare as a city with impossibly large blocks of stone (impossible for ancient humans to move). Compared to these other formations this doesn't look artificial at all! (Image from here.)
Yonaguni Formation, Japan. Nature is beautiful enough but the New Agey weirdos just can't resist putting badly photoshopped pictures online claiming to be this (if you look you'll find them. A fourth-grader could fake pictures better.)
*The hilarious thing about that Mars-face book was the gyrations the author went through trying to attach mathematical significance to the location of the face. (Which as shown above turns out to have been an optical illusion of lighting anyway.) The author's big claim? The "face" is located at the latitude of the arctangent of pi over e. (Remember Spaceballs? "You are my uncle's father's brother's cousin's former roommate." "What's that make us?" "Absolutely nothing!") So did the Martians want us to figure it out or not? Kind of seems like they would have made it a little easier than that (fortunately they used the same coordinate system that we do in the U.S.) With hidden codes like this, it's kind of like how Satan is supposedly this master of deception, but somehow he can't resist putting his little signature on things? Come on, even U.S. intelligence is smarter than that! (Not content with the face on Mars, this author also wrote about the "secret" history and mission of NASA. I mean come on. There should be a Bonferroni correction for conspiracy theories.)