Best known for its stunning marble caves is the Oregon Caves National Monument. It was discovered in 1874 and became a tourist attraction in the 1890s. In 1909, it was declared as a US National Monument by then president, William Howard Taft.

The thing that?s so special about the Oregon Caves National Monument is that it is composed of a 3.5 mile marble cave that is also the home to one of the largest collections of endemic cave dwelling insects in the country. It has also been the site where fossils of jaguar and grizzly bears from the Pleistocene era was found.

Access to the Oregon Caves National Monument comes with a fee, but it will definitely be worth the trip as the tour takes 90 minutes of fun and wonders. It is open from March to November, except on Thanksgiving Day.