The craggy rock formations, clouds and vistas in Yellowstone National Park lend themselves to black and white photography.
When you get home and look over your (hundreds of?) photos, take a few minutes to change them to black and white to see how they look. You'll be surprised at how good some of them look. A 16x9 enlargement with a barn wood frame of your favorite black and white gives any room that rustic Montana look.
The above picture was taken at the Mt. Haynes overlook about seven miles from the entrance at West Yellowstone, Montana. There's a sign and parking area for it and it's a nice stop on the way to Old Faithful. Converting this to black and white really brought out the crevices of the overlook, I like how the steam looks rising from the Madison River.
I converted this picture to more of a sepia tone. Monotone shots can express "emotional" atmospheric conditions, such as here where the morning sunrise is starting to warm the park and cause steam to rise from the river.