Hidden Unseen: 2013-12-01

Wolfe Creek Crater in Australia

Wolfe Creek Crater is a well-preserved meteorite impact crater located in the flat plains of the northeastern edge of the Great Sandy Desert in Western Australia, some 150 km south of the town of Halls Creek. The crater is considered the second largest in the world from which meteorite fragments have been collected, after the famous Barringer Crater in Arizona. Because of its excellent preservation, the crater clearly shows the classic features that result from a large meteorite striking the Earth.

Wolfe Creek Crater measures roughly 880 meters in diameter, and the mostly flat crater floor sits some 55 meters below the crater rim and some 25 meters below the sand plain outside of the crater. At the crater’s center, the ground rises slightly. Here grows some surprisingly large trees that draw moisture from the crater’s water reserves that remain after summer rains.

The crater was formed 300,000 years ago when a meteorite weighing more than 50,000 metric tons struck the Earth at an estimated 15 kilometers per second. The impact punctured a hole on the surface and shattered rocks well below the ground surface, and the intense heat of the impact liquefied both the meteorite and the nearby terrestrial rocks. These rocks now take the form of rusted balls of iron-shale that occur in the vicinity. These balls can weigh as much as 250 kilograms apiece.

The Wolfe Creek Crater had been known for long by Australia’s Aboriginal people before it was identified by aerial survey in 1947. The locals refer to the crater as “Gandimalal” and it is prominent in art from the region. The European name for the crater comes from a nearby creek, which was in turn named after Robert Wolfe, a prospector and storekeeper during the gold rush that established the town of Halls Creek.

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Pingualuit Impact Crater, Canada

In the far north of Quebec, a province in Canada, lies an exceptional natural wonder – a circular lake of blue waters confined within the walls of an ancient but well-preserved meteorite crater. Largely unknown to the outside world, the lake-filled crater had long been known to local Inuit who knew it as the "Crystal Eye of Nunavik" for its clear water. The lake was first observed by the crew of a United States Army Air Force plane in June 1943, who used the lake’s unusual shape and color for navigation, but pictures of it weren’t made public until 1950.

When Ontario diamond prospector Frederick W. Chubb saw the photographs, he became interested in it. He hoped that this might be an extinct volcano and there was a possibility to find diamonds nearby. Chubb sought the opinion of geologist V. Ben Meen of the Royal Ontario Museum, who immediately saw the possibility of an impact crater. Meen organized an expedition to this remote area together with Chubb. It was on this trip that Meen proposed the name "Chubb Crater". Meen organized two more expeditions to the crater, and from the data collected from the site, concluded that the structure was a meteorite crater produced from an impact roughly 1.4 million years ago.

The name of the lake was later changed to "New Quebec Crater" at the request of the Quebec Geographic Board. In 1999, the name was again changed, to "Pingualuit". The crater and the surrounding area are now part of Pingualuit National Park.

Pingualuit crater is 3.44 km in diameter. The crater rises 160 meters above the surrounding tundra and is 400 meters deep. A 267 meters deep body of water fills the depression, forming one of the deepest lakes in North America. The lake also holds some of the purest fresh water in the world, with a salinity level of less than 3 ppm. The lake has no inlets or apparent outlets, so the water accumulates solely from rain and snow and is only lost through evaporation. It is also one of most transparent lakes in the world with visibilities up to 35 meters.

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Kalavantin Durg (Prabalgad Fort), India

Prabalgad Fort, also known as Kalavantin Durg (Kalavantin’s Fort), is located between Matheran and Panvel in the Indian state of Maharashtra, at an elevation of 2,300 feet in the Western Ghats. It was built at the pinnacle of a rocky plateau very close to Matheran. Previously, the fort was known as Muranjan until it was taken over and renamed by the Maratha forces under Shivaji's rule.

The fort can be approached via a chillingly steep climb. The steps leading up to the fort were cut into the rock of the hill. There are no safety rails on the edge and no ropes on the wall to grab on to. The hardest part is the descent, especially if you have vertigo.

According to legend the fort was built for a queen named Kalavantin but that really seems to be all that anybody knows. Around 1458 Malik Ahmad, the prime minister of the kingdom of Ahmednagar, took over the fort during his conquest of Konkan. The Mughals took control of Prabalgad along with Kalyan, Mahuli, Karnala and a number of other forts after Sambhaji's death.

The fort was conquered by Shivaji from the Mughals in 1657, after he establishing himself in the Kalyan-Bhivandi area. At the time of the attack the fort was governed by Kesar Singh, a Mughal sardar, and was the only fort to put up a strong resistance. On seeing the signs of defeat the women in the fort performed Jauhar, a tradition of self immolation to ensure an honorable and respectful death. Singh died during the battle in October 1657, Shivaji in an act of kindness allowed Singh's mother and her grandchild a safe passage out.

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