Virtual Cave
http://www.goodearthgraphics.com/virtcave/index.html

From the comfort of your keyboard, browse the wonders of the underground! As a caver and photographer for over 30 years, they have collected images from caves all over the world. This site tells the story of caves in words and pictures: what’s in them and how it got there. Because caves are so diverse, they have split them into four underground realms. Grab three sources of light, a helmet, some sturdy boots, and your mouse, and have fun exploring – there LOTS to see! Please treat all caves with respect as these fragile formations are easily damaged. Their motto is: “cave softly and leave no trace of your visit.” This has been added to Reference Resources Subject Tracer™ Information Blog.