A monolith is a geological feature consisting of a single massive stone or rock, such as some mountains. Erosion usually exposes the geological formations, which are often made of very hard and solid igneous or metamorphic rock. In architecture, the term has considerable overlap with megalith, which is normally used for prehistory, and may be used in the contexts of rock-cut architecture that remains attached to solid rock, as in monolithic church, or for exceptionally large stones such as obelisks, statues, monolithic columns or large architraves, that may have been moved a considerable distance after quarrying. The term can also refer to a single great stone often in the form of an obelisk or column, or a massive structure.
Recently, mysterious monoliths have been appearing across the world, including in Utah, Romania, California, and New Mexico. These monoliths are long vertical slabs of metal, each 10 to 12 feet tall, and they appear with no warning and disappear just as quickly.
