We drove from the Kīlauea Iki Overlook around the other way to get to the Thurston Lava Tube, a huge tunnel left behind when the lava drained away. Thurston Lava Tube This huge tunnel was left behind when a subterranean
Postojna Cave is near Postojna, southwestern Slovenia. It is one of the largest cave systems in Europe. June 2015 Postojna Cave system reached a new length. It is now officially 24,120 m (79,130 ft) long. Cave divers have extended the
The Holmes Stereoscope Stereoscopes are an old invention that allows photos to be viewed in 3-D. The first stereoscopes date to around 1838. They were very popular. There were various models available when Oliver Wendell Holmes invented the hand stereopticon,