Retired teacher Geoff Ostling displays his tattooed skin at a portrait session at his home in Petersham on May 11, 2009 in Sydney, Australia. The 62-year old has pledged to donate his skin to the National Gallery in Canberra after his death. Ostling, who did not get his first tattoo until he was in his forties, is now covered in the artwork by artist eX de Merci from neck to ankle with the theme 'all the flowers of a Sydney garden'. (Photo by Lisa Maree Williams/Getty Images)

Dancers from the Yarrabah community perform during the Laura Aboriginal Dance Festival on June 18, 2011 in Laura, Australia. The Laura Aboriginal Dance Festival is a celebration of aboriginal dance and culture that takes place Biennially in Cape York Peninsula at the site of a traditional Bora ground that is sacred to the aboriginal community and surrounded by some of the oldest rock art in the world. Over 5000 visitors attend the festival, offering a unique insight into the community and providing an opportunity to spread cultural traditions to new generations. The festival takes place June 17-19. (Photo by Mark Kolbe/Getty Images for Tourism Queensland)

A girl looks up at the trophy she won after competing in a child beauty pageant at Northcote Town Hall on July 30, 2011 in Melbourne, Australia. The controversial child beauty competition, kicked off today in Melbourne despite complaints and demonstrations by pageant opponents. Organised by the US-based pageant company that produces reality TV show “Toddlers and Tiaras”, Australian contestants will have the opportunity to pose with the reality show star, six year-old Eden Wood. (Photo by Scott Barbour/Getty Images)

These spectacular images of the universe are the finalists in the 2016 CWAS “David Malin” awards. The annual competition, which celebrates the best astronomy images taken by Australian photographers, is part of AstroFest 2016. The winners will be announced on 16 July. An associated exhibition opens the following day at the CSIRO Parkes Observatory visitors centre, and a second exhibition will also travel to selected venues around Australia. Here: Mars and its Rival Antares and the Rho Ophiuchi cloud complex. (Photo by Phil Hart/CWAS/The Guardian)

The current world Champions in the Men's and Women's RS:X, Piotr Myszka of Poland and Blanca Manchon of Spain arrive at Bathers Beach carrying the ISAF World Championships Flag to be raised to officially open the 2011 ISAF Sailing World Championships on December 2, 2011 in Perth, Australia. (Photo by Mark Dadswell/Getty Images)

Canadian escape artist Dean Gunnarson attempts to work his way out of a straight jacket while hanging from a crane by a rope which is on fire during a Royal Melbourne Show preview at the Melbourne Showgrounds on September 23, 2011 in Melbourne, Australia. The Royal Melbourne Show officially kicks off tomorrow, and continues until October 4. (Photo by Mark Dadswell/Getty Images)

Son doong cave is a cave in Phong Nha-Kẻ Bàng National Park, Bố Trạch district, Quảng Bình Province, Vietnam. Currently the biggest known cave in the world, the cave is located near the Laos-Vietnam border. Inside is a large, fast-flowing underground river.
In early August 2013, the first tourist group explored the cave on a guided tour at a cost of US$3,000 each. The group had six members from Australia, Norway, Russia and USA and spent 7 days and 6 nights for the tour. Next exploration trips will be arranged.