A cave or cavern is a natural void in the ground a space large enough for a human to enter. Caves form by the weathering of rock and extend deep underground; the word cave can refer to much smaller openings such as sea caves, rock shelters, grottos, though speaking a cave is exogene, meaning it is deeper than its opening is wide, a rock shelter is endogene. Speleology is the science of study of all aspects of caves and the cave environment. Visiting or exploring caves for recreation may be called caving, potholing, or spelunking; the formation and development of caves is known as speleogenesis. Caves can range in size, are formed by various geological processes; these may involve a combination of chemical processes, erosion by water, tectonic forces, microorganisms and atmospheric influences. Isotopic dating techniques can be applied to cave sediments, to determine the timescale of the geological events which formed and shaped present-day caves, it is estimated that a cave cannot be more than 3,000 metres vertically beneath the surface due to the pressure of overlying rocks.

This does not, impose a maximum depth for a cave, measured from its highest entrance to its lowest point, as the amount of rock above the lowest point is dependent on the topography of the landscape above it. For karst caves the maximum depth is determined on the basis of the lower limit of karst forming processes, coinciding with the base of the soluble carbonate rocks. Most caves are formed in limestone by dissolution. Caves can be classified in various other ways as well, including a contrast between active and relict: active caves have water flowing through them. Types of active caves include inflow caves, outflow caves, through caves. Solutional caves or karst caves are the most occurring caves; such caves form in rock, soluble. Rock is dissolved by natural acid in groundwater that seeps through bedding planes, faults and comparable features. Over time cracks enlarge to become caves and cave systems; the largest and most abundant solutional caves are located in limestone. Limestone dissolves under the action of rainwater and groundwater charged with H2CO3 and occurring organic acids.

The dissolution process produces a distinctive landform known as karst, characterized by sinkholes and underground drainage. Limestone caves are adorned with calcium carbonate formations produced through slow precipitation; these include flowstones, stalagmites, soda straws and columns. These secondary mineral deposits in caves are called speleothems; the portions of a solutional cave that are below the water table or the local level of the groundwater will be flooded. Lechuguilla Cave in New Mexico and nearby Carlsbad Cavern are now believed to be examples of another type of solutional cave, they were formed by H2S gas rising from below. This gas mixes with groundwater and forms H2SO4; the acid dissolves the limestone from below, rather than from above, by acidic water percolating from the surface. Caves formed at the same time. Lava tubes are the most common primary caves; as lava flows downhill, its surface solidifies. Hot liquid lava continues to flow under that crust, if most of it flows out, a hollow tube remains.

Such caves can be found in the Canary Islands, Jeju-do, the basaltic plains of Eastern Idaho, in other places. Kazumura Cave near Hilo, Hawaii is a remarkably deep lava tube. Lava caves are not limited to lava tubes. Other caves formed through volcanic activity include rifts, lava molds, open vertical conduits, blisters, among others. Sea caves are found along coasts around the world. A special case is littoral caves, which are formed by wave action in zones of weakness in sea cliffs; these weaknesses are faults, but they may be dykes or bedding-plane contacts. Some wave-cut caves are now above sea level because of uplift. Elsewhere, in places such as Thailand's Phang Nga Bay, solutional caves have been flooded by the sea and are now subject to littoral erosion. Sea caves are around 5 to 50 metres in length, but may exceed 300 metres. Corrasional or erosional caves are those that form by erosion by flowing streams carrying rocks and other sediments; these can form in any type including hard rocks such as granite.

There must be some zone of weakness to guide the water, such as a fault or joint. A subtype of the erosional cave is the aeolian cave, carved by wind-born sediments. Many caves formed by solutional processes undergo a subsequent phase of erosional or vadose enlargement where active streams or rivers pass through them. Glacier caves are formed by flowing water within and under glaciers; the cavities are influenced by the slow flow of the ice, which tends to collapse the caves again. Glacier caves are sometimes misidentified as "ice caves", though this latter term is properly reserved for bedrock caves that contain year-round ice formations. Fracture caves are formed when layers of more soluble minerals, such as gypsum, dissolve out from between layers of less soluble rock; these rocks fracture and collapse in blocks of stone

Mineral King

Mineral King is a subalpine glacial valley located in the southern part of Sequoia National Park, in the U. S. state of California. The valley lies at the headwaters of the East Fork of the Kaweah River, which rises at the eastern part of the valley and flows northwest. Accessed by a long and narrow winding road, the valley is popular with backpackers and hikers; the valley was inhabited by the Yokut tribe. In the 1870s, silver was discovered on the slopes of a mountain overlooking Mineral King. Mineral King Road was built in 1873 and was improved throughout the early 20th century. A proposal by Walt Disney Productions to build a ski resort called "Disney's Mineral King Ski Resort" in the valley in the 1960s was stopped by preservationists. In 1978, the valley became part of Sequoia National Park; the name Mineral King refers to the historic mining camps and towns in and near the valley, including Silver City and Cabin Cove. The settlements as a whole are referred to as the Mineral King Road Cultural Landscape, was added to the National Register of Historic Places in 2003.

Mineral King is a 7.5-mile - 1-mile - wide glacial valley in the southern Sierra Nevada. The valley floor lies at an elevation of 7,400 feet, while the granite peaks rising above the head of the valley reach heights of 11,000 feet or more; as the crow flies, it is located about 20 miles southeast of Three Rivers, near the confluence of the East Fork Kaweah River and Middle Fork Kaweah River. The valley floor is an expanse of open meadows with a narrow strip of riparian vegetation, including short trees and bushes, along the East Fork Kaweah River; as the flat meadows give way to rocky slopes, there are many congregations of conifers that climb the slopes to the tree line. Above the tree line, there are sheer or sheer granite walls that slope up to form Sawtooth Peak, Empire Mountain, Mineral Peak, Hengst Peak and others. There are two prominent mountain passes leading out of Mineral King: Timber Gap, which leads into the Middle Fork Kaweah River drainage' and Farewell Gap at the valley head, which leads into the Kern River drainage.

The first half of the valley runs from south to north and the second half runs from east to west. Fed by snowmelt and abundant lakes in granite bowls at the upstream-most section of the valley, creeks plunge down the steep valley walls as long and twisting waterfalls; these include Tufa Falls, Crystal Creek Falls, Franklin Falls, in upstream order. This section of the valley is dotted with tributary gorges that fan out from the main canyon. Lakes in this section of the valley include the Mosquito Lakes, Eagle Lake, the Franklin Lakes, the Crystal Lakes. From the end of the valley, the East Fork Kaweah River drops over Mineral King Falls and East Fork Falls, before continuing down a steep and narrow gorge, following Mineral King Road. Mineral King is one of the oldest communities in the High Sierra, with many families owning cabins for six or seven generations. Many of the communities have been inhabited since. Evidence suggests that Native Americans long ago used Mineral King to hunt in; these Native American groups included the Tübatulabal.

The Yokuts' main settlements had their main villages in the broad valley adjoining and in the present-day site of Lake Kaweah. They created summer settlements on the valley floor and around the area, to be the site of Atwell Mill; the primary purpose of these summer settlements was hunting and trading with the Paiutes, who lived east of the Sierra Nevada. But prior to contact with white settlers, the valley became taboo to the Wikchúmni Yokut tribe, no humans had inhabited it for some time; the first explorer of European descent known to have visited Mineral King was the Irishman Harry "Parole" O'Farrell, in 1862. While employed as hunters for a trail crew building the Hockett toll trail from Visalia to Independence, O'Farrell and a Paiute companion found the valley from the south, over Farewell Gap. Attracted by the promise of mineral riches, O'Farrell returned to prospect and build a summer settlement on the East Fork of the Kaweah River, which came to be called Harry's Bend. In the 1870s and 1880s, assays of precious metals in White Chief Canyon and on Empire Mountain led to the boomtown of Beulah.

The first discovery of silver in the Mineral King Valley occurred in 1872, below Mineral Peak and Empire Mountain. Following the discovery, the Mineral King Wagon and Toll Road Company was established in December 1873 to build a wagon road; the first routing of Mineral King Road followed the East Fork Canyon's south side. Until access to Mineral King was by rough tracks. A second discovery of silver in 1878 drew more prospectors to the Mineral King area and a second Mineral King Road, following a different route up the north side of the canyon, was constructed in 1879; this created the route for much of the present-day Mineral King Road. The Mineral King Road passes through two groves of giant sequoias, the Redwood Creek Grove and the Atwell Grove. In 1890 the groves were included in the boundaries of the newly established Sequoia National Park, encompassing the central portion of the road. Mineral King itself was excluded from the new park; the Mineral King entrance was the most used gateway to the park until 1903.

A Tom Fowler purchased the Empire Mine the largest mine in the area, created the Empire Gold and Silver Mining Company. The lowermost part of the road was rebuilt in 1915 to its present-day route. Over time, the minerals were found to be unprofitable to extract from their ore and no significant mining took place, but the valley kept its hopeful name: Mineral King. By the 1920s and as

Bhawana Somaaya

Bhawana Somaaya is an Indian film journalist, critic and historian. She has been honoured with the Padma Shri in the year 2017 by the honourable President of India - Mr Pranab Mukherjee. Starting her career as film reporter in 1978, she went to work with several film magazines, through the 1980s and 1990s, she remained editor of Screen, a leading film magazine, from 2000 to 2007. She has written over 13 books on history of Hindi cinema and biographies of Bollywood stars, including Salaam Bollywood, The Story So Far and her trilogy, Amitabh Bachchan – The Legend, Bachchanalia – The Films And Memorabilia of Amitabh Bachchan and Amitabh Lexicon. Somaaya was brought up in Mumbai, she is the youngest child amongst her eight siblings. She did her schooling from Our Lady of Good Counsel High School in Sion, Mumbai and is trained in Bharatnatyam dance at Vallabh Sangeetalaya in Andheri West. After her schooling, she did her graduation in Psychology and acquired a degree in L. L. B. from Government Law College, University of Mumbai.

She studied Journalism at K. C. College, Mumbai. Somaaya started her career as a film journalist and columnist with in 1978, writing the column, "Casually Speaking" in film weekly, Cinema Journal published by The Free Press Journal. After working in Super magazine, she joined the Movie magazine published by India Book House as an assistant editor and became co-editor in 1985, worked here till 1988. In 1989, she became the editor of a film magazine by Chitralekha Group; this was followed by her tenure as editor of noted film weekly, Screen from 2000 to 2007. Meanwhile, she has worked as costume designer, for actress Shabana Azmi in films like Kaamyaab, Aaj Ka M. L. A. Ram Avtar and Main Azaad Hoon. Over the years, her columns have appeared in publications like The Observer, Janmabhoomi, The Hindu, The Hindustan Times and Indian Express. In 1999, she started her career with biography, Amitabh: The Legend; this led to biographies of other film celebrities, like Lata Mangeshkar and Hema Malini, plus two more book of Amitabh Bachchan, Bachchanalia – The Films And Memorabilia of Amitabh Bachchan and Amitabh Lexicon.

Bachchanalia was co-authored by the Osians Centre for Archiving, Research & Development and included publicity material from the 40 years of his film career. She has written books on Hindi cinema history, Salaam Bollywood and Take 25 – Star Insights and Attitudes, released by actress Rekha at a function in Mumbai and entailed Somaaya's 25 years as a film journalist; this was followed by The Story So Far published by Indian Express and Talking Cinema: Conversations with Actors and Film-Makers. Shifting to television, in 2008, when she joined Swastik Pictures, a television production company, which made TV series, Amber Dhara as a media consultant. In May 2012, she started appearing on air, as a Friday-film reviewer, BIG FM 92.7, Reliance Media's FM radio station. In 2012, she joined the newly launched film trade magazine. Bhawana Somaaya. Amitabh Bachchan: The Legend. Macmillan India Limited. ISBN 978-0-333-93355-8. Bhawana Somaaya. Salaam Bollywood: The Pain and the Passion. Spantech & Lancer. ISBN 978-1-897829-54-7.

Bhawana Somaaya. Take 25: Star Insights & Attitudes. Sambhav Publishers. ISBN 978-81-901354-1-2. Bhawana Somaaya; the Story So Far. Indian Express Group. Bhawana Somaaya. Cinema Images And Issues. Rupa Publications. ISBN 978-8129103703. Bhawana Somaaya. "Lata Mangeshkar". In Malvika Singh. Freeing the Spirit: The Iconic Women of Modern India. New York. ISBN 978-0-14-310082-9. Bhawana Somaaya. Hema Malini: The Authorized Biography. Lotus Collection. ISBN 978-81-7436-467-8. Bhawana Somaaya. Fragmented Frames: Reflections of a Critic. Pustak Mahal. ISBN 978-81-223-1016-0. Bhawana Somaaya. Krishna-The God Who Lived As Man. Pustak Mahal. ISBN 978-81-223-1027-6. Bhawana Somaaya. Bachchanalia: The Films and Memorabilia of Amitabh Bachchan. Osian's-Connoisseurs of Art. ISBN 978-81-8174-027-4. Bhawana Somaaya. Mother Maiden Mistress: Women in Hindi Cinema, 1950–2010. HarperCollins, India. ISBN 978-81-7223-859-9. Bhawana Somaaya. Amitabh Lexicon. Pustak Mahal. ISBN 978-8122311891. Bhawana Somaaya. Talking Cinema: Conversations with Actors and Film-Makers.

HarperCollins. ISBN 978-9350296455. Archived from the original on 9 August 2013. Retrieved 19 August 2013. Bhavana Somaaya, website Bhawana Somaaya on Twitter