All I get with national parks is "this national park is great", but no way of determining which ones I should go for, and what makes them unique from all the other national parks.
The truth of the matter is: every national park in the US is unique and has different things to offer. Almost all of them offer some form of hiking and other outdoor recreation, but their scenic beauty is what makes them different.

Mesa Verde National Park -- the site of old Native American cliff dwellings, in a very different setting.

Grand Canyon -- the southern most canyon of the "Grand Staircase". Unless you hike it, you are on the top looking down with the Colorado River at the very bottom.

Zion - another part of the "Grand Staircase" where you are looking at beautiful red rocks and formations, but you are at the bottom looking UP.

Bryce Canyon - a helluva place to lose a cow, as one historic rancher said. Part of the "Grand Staircase", this place is spires and canyon, once again looking from the top, but totally different from the Grand Canyon.

Capitol Reef and Canyonlands National Parks - northernmost section of the "Grand Staircase" geologically, but mostly different from the GCNP.

Joshua Tree National Park - where a huge amount of a specific plant called joshua trees grow all in one place. In southern Arizona, there is Organ Pipe National Monument -- thousands of organ pipe cacti grow there -- and Saguaro National Park --- where thousands of saguaro cacti all grow in the same area.

This summer, my husband and I are planning to check out a lot more national parks and national military/historic parks and national monuments. They're all different. Gettysburg is of course the site of the biggest battle of the Civil War, and we hope to finally get there after 2 other failed attempts. Wind Cave National Park, which is a specific type of a cave. Devil's Tower. Yellowstone (full of lakes, hot springs, hot pools and geysters), Grand Tetons (a majestic set of rugged mountains), Cuyahoga Valley in OH, and so much more. Some day I'd like to say that I've been to all of the national parks and most of the monuments -- a bucket list -- because they're all unique.


Donna