1. Well Of Chand Baori – India:
Chand Baori is one of the oldest and most attractive landmarks in Rajasthan. It was built by King Chanda of the Chauhan Dynasty between AD 800 and AD 900 and was dedicated to Hashat Mata, Goddess of Joy and Happiness upon completion. The state of Rajasthan is extremely arid, and the design and final structure of Chand Baori was intended to conserve as much water as possible. At the bottom of the well, the air remains 5-6 degrees cooler than at the surface, and Chand Baori was used as a community gathering place for locals during periods of intense heat. One side of the well has a pavilion and resting room for the royals.
2. Kimberley Big Hole – South Africa:
The Big Hole, Open Mine, Kimberley Mine or Tim Kuilmine is an open-pit and underground mine in Kimberley, South Africa, and claimed to be the largest hole excavated by hand, although this claim is disputed.
As the centre for the diamond fever of the late 19th century, its foundations began to be dug in 1871 when a diamond was found on a small hill called Colesberg Koppie. Digging began and only a few months later more than 30 000 men were frantically excavating for diamonds in an area covering 300m by 200m. They made short work of the hill and soon plunged down into the earth to a depth of 1100 metres to create what came to be known simply as the ‘Big Hole’. 28 million tons of dirt was removed, yielding 14.5 million carats of diamonds and resulting in the creation of the largest man made hole in the world. It was here that the famous Star of Africa was found, a magnificent 83.5 carat diamond.
3. Xiaozhai Tiankeng – China:
The Xiaozhai Tiankeng, also known as the Heavenly Pit, is the world’s deepest sinkhole. It is located in Fengjie County of Chongqing Municipality.
The Xiaozhai Tiankeng is 626 metres long, 537 metres wide, and between 511 to 662 metres deep, with vertical walls. The sinkhole is a doubly nested structure—the upper bowl is 320 metres deep, the lower bowl is 342 metres deep, and the two bowls are on average 257 to 268 m across. Between both these steps is a sloping ledge, formed due to soil trapped in the limestone. In the rainy season, a waterfall can be seen at the mouth of the sinkhole.