Oregon Caves National Monument is small in size, 480 acres, but rich in diversity. Above ground, the monument encompasses a remnant old-growth coniferous forest including a Douglas-fir tree with the widest known girth in Oregon. Three hiking trails access this forest. Below ground is a marble cave created by natural forces over hundreds of thousands of years in one of the world's most diverse geologic realms.

Oregon Caves National Monument is a collection of chambers and passages that experts estimate are 3 to 5 million years old. This is a geologic wonderland for countless visitors between March and Thanksgiving each year.

Oregon Caves National Monument is one of five national parks or monuments in the state. The others are Crater Lake National Park, John Day Fossil Beds National Monument and Fort Clatsop National Memorial.

Take the unique tour through the Oregon Caves, a trek along an asphalt trail complete with low ceilings, narrow passages and an occasional tight squeeze.

Some quick rules to keep in mind:

The tour was a captivating half-mile walk through a myriad of chambers and rooms with fascinating formations. And, of course, there are plenty of names - the Imagination Room, soda straw stalagmites, the Petrified Forest room, the Banana Grove, the River Stix, Paradise Lost, the massive Ghost Room and more.

Tour interpretor Julie Anderson says the caves are 3 million to 5 million years old. Each person who visit finds something special.

"People are fascinated by it," Julie says. "It's human interest. A cave can tell us about ecology. It brings a tells us all so much about the underground world and it's all knew to most people.".

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