This was discovered in 1878, and its cavern system is teemed with columns, mud flows, stalagmites, stalactites, and mirrored pools. Explore the Great Stalacpipe Organ with its massive and solenoid fired strikers. The caverns are yellow, brown, or red because of the mix of chemicals and minerals. The Giant's Hall, Pluto's Ghost as well as some draperies are a sight to behold.
This is formed by 100 million years of cretaceous limestone. It boasts of three-dimensional mazes with each walls covered with crystals or sparkling speleothems that are intricately layered to form a beautiful maze. Cave tours will take you to some enchanted areas with caverns, walls and ceilings lined with corals, soda straws, stalagmites, and coral trees.
This is a hair rising experience that will leave you both excited and scared at the same time. This is for the brave who can descend 26 stories underground to explore the caverns deep within. Ruby Falls is a 145-foot high underground waterfall that is formed by a large vertical shaft. You can see the stream that is fed by both rainwater and natural springs as it collects into a pool into the cave floor.
This is a site for the longest continuing lava tube in the United States. It is said that lava cascaded from volcanoes that erupted nearby. It attracts over 170,000 cave tours every year. A view of Mt. St Helens can be seen in the region.
This is an archaeological site, which is also developed for cave tours. The moaning cave is located at the bottom of a spacious vertical shaft at 165 feet tall; you continue descending the 100-foot spiral staircase until you reach the cavern at around 410 feet in depth. Here, you can explore the oldest human remains of pre-historic people in the Americas. The cave has been a resting place for people who fell in its opening; thus, the term named as "moaning cave".