There are not too many places left on the planet that remain unexplored - that you can go to and realistically claim to have left the first footprint.
One way to do that, though, is by going underground.
"It is probably one of the only places you can get to on the planet and put a foot where nobody else has been," says Bob Kershaw, an experienced caver and member of the Illawarra Speleological Society (ISS).
Kershaw had that experience on an ISS expedition to the Ningbing Ranges in Western Australia where they surveyed and mapped an extensive and previously undiscovered cave system.
"We found some fantastic stuff," Kershaw says. "There aren't many places left like that.
"Some West Australians from the local area came and joined us for a weekend so we took them through the area and they were gobsmacked at what we had found."
The ISS, which has members ranging in age from young children to 80-year-olds, celebrates its 50th anniversary next year.
As well as putting on expeditions to nearby caves every month, the club aims to get out to far flung caving hotspots like the Ningbings or the Nullabor at least every other year.
Club secretary Alison Scobie says there are no suitable caves in the Illawarra, with Bungonia near Goulburn probably the closest one, while Bendethera near Moruya and Jenolan in the Blue Mountains are other caves the society regularly visit.
The ISS has also been working with the Canberra Speleological Society and the Office of Environmental Heritage to restore the caves at Wyanbene in the Deua National Park near Braidwood.
"It's an environmental organisation as well as an exploration, surveying and just-going-out-there-for-an-adventure recreational organisation," Scobie says.
Like many spelunkers, Scobie and Kershaw both got their first taste of caving in the Scouts.
Most cavers share a love of nature and being outdoors - although a liking for dark, confined spaces is definitely necessary as well.
"I was introduced to caving when I was in Scouts and when I left I wanted to still be able to get out and camp and explore so I joined the Speleos," Scobie says.
"We go camping and caving and if we go underground sometimes that's okay.
"There are just so many beautiful things you can see in caves."