Mystery Photo 52 shows a route marker in Oregon Caves National Monument .

Located in the northern Siskiyou Mountains, a coastal mountain range in southwestern Oregon, venerable Oregon Caves National Monument (proclaimed 1909) preserves old growth Douglas fir forest, a collection of rustic/historic buildings, and a marble cave that is both geologically interesting and visually appealing. The park is rather difficult to get to, and that largely explains why only 80,385 recreational visits were tallied in 2011.

Cave tours are offered at Oregon Caves from mid-April through early November. Since safety and resource protection are major concerns, special care is taken to insure that people don’t stray off the tour routes and wander into areas of the cavern system that are closed to visitors.

Route markers have played an important role since the earliest days of cave exploration. The arrow shown in the mystery photo is a route indicator that a cave explorer made with the sooty flame from a carbide lamp. The soot is non-toxic and easily removable, so it’s considered fairly harmless.

Congratulations to the Traveler readers who ID-ed the photo: celbert, Eric, Eric B, Moon Pie, and s. All are eligible for our monthly prize drawing and a chance to win a copy of David and Kay Scott's The Complete Guide To The National Park Lodges, 7th Edition.