It’s time to test your knowledge about the 424 units of the National Park System. How much do you really know? Try answering these quiz questions before looking at the bottom of the piece. You might learn something totally new from the questions and bits of trivia. There’s so much to learn about the parks!

Thirty-one species of cacti live in the starkly beautiful Organ Pipe Cactus National Monument in the Sonoran Desert, along with bighorn sheep, pronghorns, javelinas, kangaroo rats, rare pupfish and all kinds of reptiles and birds. But the green desert is also home to a 30-mile stretch of America’s steel border wall and warning signs had this traveler anxious that “smuggling and illegal immigration may be encountered in this area.”

Installation of a new liner for the Quitobaquito Pond in Organ Pipe Cactus National Monument in southern Arizona will require that the road leading to the pond and surrounding area will be closed for four weeks.