karst Forest grows in a giant, 630ft-deep sinkhole Rob Beschizza

spelunking Video finally reveals what's at the bottom of Yemen's Well of Hell David Pescovitz

caves A Missouri cave filled with 1,000-year-old indigenous paintings sold at auction and the Osage Nation want it back David Pescovitz

circadian rhythms Stefania Follini was isolated in a cave for 131 days for science Andrea James

caves Watch: cycling to work through cavernous limestone mines turned into a business park Rob Beschizza

dance your cares away These otherworldly caves in Bermuda were the birthplace of Fraggle Rock David Pescovitz

caves All 12 boys rescued from Thai cave Rob Beschizza

Guizhou The last of China's cave dwellers want nothing to do with modern housing Séamus Bellamy

glow worms WATCH: Remarkable 4K timelapse of glow worm cave in NZ Andrea James