The Daily Croissant

"The Pico Cão Grande (Great Dog Peak) is a landmark needle-shaped volcanic plug peak in São Tomé and Príncipe, located in the south of São Tomé Island in Obo National Park." 

"A volcanic plug, also called a volcanic neck, is a volcanic landform created when magma hardens within a vent on an active volcano. A natural monolith is a mountain or large rock formation consisting of a single massive stone. Both types of these geological structures are similar in that they are often steeply rising above the surrounding terrain. The unusual appearance and the buildings which are often located on these structures, amaze visitors and attract them to come back again."

A few kilometers from the north-western German city of Dermold in the Lippe region of the country, there is a highly unusual rock formation. In an area otherwise devoid of large rocks, the soaring, slender columns of Externsteine stand out as they rise sharply and with no little majesty from the surrounding landscape. Little wonder that the site has been attracting curious visitors for thousands of years.

see also Externsteine - Walpurgisnacht, Sonnenwende, Halloween

by Stan Celestian  

"The photo above shows a layer of salt formed on the surface of Searles Lake in California. Salt, yes, but with an interesting formation process. It greatly resembles three-dimensional models of topographic maps. The process involves the evaporation of the brine to create the crusts of salts, but with an ever-decreasing level of brine. The unique aspect of this formation is that the brine level apparently dropped in discrete stages. This allowed a ledge of salt to be formed distinct from those above and below. The somewhat regular spacing of the ledges (which so closely resembles those of contour lines) must have formed over daily cycles of evaporation during a time in which conditions of temperature and evaporation rates were very constant. Counting the ledges indicates this period of constancy to be about two weeks."

Strangely Round Rocks of "Unknown Origin"

Well, saying "unknown origin" is an obvious exaggeration, since it is widely assumed that they must be sedimentary concretions, and were created by cementation of mud stone, coastal erosion, time and elements, just like any other unusual rock formation.

Yet their bizarre cracked shells, often perfectly spherical shape and unexpected locations remain largely unexplained and keeps them regarded as a "geological mystery". Not to mention other theories: are they fossils? alien eggs? weird energy storage devices from a crashed alien ship? Some even say that they are the... Great Balls of Fire (that fell down on Earth in Biblical times).

"Tucked away in the Northern Ural Mountains of Russia, seven massive rock formations inexplicably explode from the flat landscape around them. Jutting up to heights of over 200 feet, the Manpupuner Rock Formations have no obvious origin and command a powerful spiritual presence for visitors.  

The Manpupuner Formations, also known as the Seven Strong Men, are more or less unknown outside of Russia. Akin to the Easter Island giants, the seven formations are mysterious, starkly contrasting their plateau environment. Likely some sort of karst formation, the rocks feel like the remnants of some long lost civilization."