After the intriguing #500 which took a long time to solve, we have now had two rapid ones in a row.
So this might be a little bit harder again.
Some areas have more hidden geology than others.
Previous WoGEs are collected by Felix on his blog and a KML file.
Sơn Đoòng Cave, Vietnam
SvarSlett17° 27′ 25″ N, 106° 17′ 15″ E
This is regarded as the world's largest cave by volume. Explored for the first time in 2009, it is over 5km long, has stalagmites up to 70m tall, a river, and a small rain forest growing in one of two large dolines. The geology of the area is limestone karst, and includes many other impressive caves. Phong Nha – Ke Bang National Park, which includes this area, is a World Heritage Site.
Over to you, Matthew!
SvarSlettWhen I saw the disappearing river I knew this challenge probably involved a large cave system. The vegetation clearly indicated a moist, tropical area. I remembered reading about a huge cave recently discovered in Vietnam, so I checked there first.
SvarSlettWOGE 504 will also be a news-worthy spot. It is now posted at:
http://matthews-woge.blogspot.com/2015/08/woge-304.html