Time to test your park unit knowledge with this National Parks Quiz and Trivia #30. See how much you know about some of the National Park Service’s 423 units and maybe learn something new.

Planning a trip to a national park or other park unit? If you are traveling to the North Rim of Grand Canyon National Park, this Traveler’s Checklist provides helpful tips for you to make the most out of a trip to this less-visited portion of the park.

When you look at photos you’ve captured during a visit to a national park unit, do you notice one or more of your shots clearly showing a division of light and dark, or energy and calm, or two different colors, or two different textures? Contributing photographer Rebecca Latson sees this phenomenon in many of her own images, calling it the “yin and yang of a composition.” In this month's column, Rebecca provides examples of this yin-yang concept and how you can look for it in nature with your camera.