Science Says This Is the Perfect U.S. Road Trip

No question—of course, you need to see the Grand Canyon. Whether you go to the South Rim or North Rim (open May through October) depends on what time of year you're driving through. 

Going for the Astronomy Festival, Geology Festival, or just beautiful scenery or a hike? Bryce Canyon National Park in Utah has it for you.

Want wilderness? The Craters of the Moon National Monument in Idaho is an official Wilderness Study Area—it's got amazing dark sky and some nature that remains "substantially uninfluenced by humans." These days, that's got to be hard to come by. 

Another "bucket list" place for multitudes of Americans is Yellowstone, known for its geysers, amazing vistas, hot mud, and the way the ecosystem has rebalanced with the reintroduction of wolves. 

Visit the second-most popular mountain on the planet, Pikes Peak. A shuttle will even take the work out of getting to the summit. And there are donuts when you get there.

Caves, cacti, desert, and fossil reefs are all at Carlsbad Caverns National Park. Spelunkers can even arrange for permits to travel off-trail on self-guided or ranger-guided trips underground. 

The Alamo as a fort was significant in the creation of San Antonio and its designation as "Military City, U.S.A." Visitors to the fort and shrine are sure to remember it.

Twenty miles of trails in the Chickasaw National Recreation Area in the Platt Historic District (formerly Platt National Park) are available for a variety of skill levels of hikers and have varying scenery among them, such as waterfalls, wildlife, Travertine Creek, ponds, and lakes.

Toltec Mounds Archaeological State Park contains ancient mounds—what remain from a "ceremonial and governmental complex"—from A.D. 650 to 1050, when the area was inhabited by American Indians.

In this day of McMansions, the size of Elvis Presley's Graceland Mansion might surprise you. The time capsule–ness of the home captures all the King's favorite 1977 kitsch. If you can't there for his birthday during Elvis week in August, the candlelight vigil is broadcast.

A key city in the opinion of both sides fighting of the Civil War, soldiers battled in Vicksburg for a long 47 days. You can see an ironclad ship, visit 1,400 monuments and memorials, and see reenactments.

There's always something to see, hear, do, and eat in the infamous French Quarter. Bourbon Street even has its own official bucket list.

No one's sinking this World War II battleship that saw action in the South Pacific in 1944 (and in the movie "USS Indianapolis: Men of Courage"). Tour it in Alabama.

Kids and adults alike can imagine their space-explorer dreams at Cape Canaveral, a historic site and home to six launch pads. See where the U.S. space program began.

The Okefenokee Swamp Park is nature like you've likely never seen it before. The Natural Wildlife Refuge covers nearly half a million acres.

Visit where the Civil War began. Located in Charleston Harbor, Fort Sumter is accessible only by boat. 

You can travel on a simple self-guided cave tour on trails 120 feet down, or you can go all in, deeper, on a four-hour guided excursion, where few humans have traveled.

The Wright Brothers weren't the only ones trying to fly, but their few moments sustained in the air in 1903 were historic. See where flight first took off, in North Carolina. 

Mount Vernon, the home of the United States' first president (and Founding Father and Revolutionary War hero, and... ) is a must-see. 'Nuff said. 

If you want to take a tour of the White House, it must be submitted through one of your members of Congress, so plan ahead. Don't try and jump the fence.

Annapolis has more 18th century structures standing than any other city in the United States; the downtown "Athens of America" draws more than 4 million visitors per year. 

Can't get enough of colonial buildings? New Castle, Delaware, was founded in the 1650s; you can tour museums and the Old New Castle Courthouse, which was the location of the colonial and state government until 1777.

Sure there are historic homes and businesses in Cape May that you've got to see, but you can't miss the lighthouses, either, all from the mid- to late 1800s.

Independence Hall once housed the bell now known as the Liberty Bell when it was just a regular ol' signal. Its significance grew over time.

If you want to climb to the top of the Statue of Liberty (or the pedestal), you'll need to get your ticket well in advance. If you don't get that ticket, you can still tour the grounds and the National Museum of Immigration. 

You won't see rivers and riverboats at Mark Twain's house in Connecticut, but you will see an amazing home and Samuel Clemens museum.

​Vanderbilt: Just that last name means that you've got to see the Breakers Mansion. The fact that it's a "70-room Italian Renaissance-style palazzo" complete with stable and carriage house just reinforces that fact. 

Climb aboard and tour the USS Constitution at the Charlestown Navy Yard. If you're making a day of military history, you're just a short walk of the Bunker Hill Monument and Museum.

Just because some trails remain off-limits during peregrine falcon nesting season doesn't mean that there aren't areas to explore in Acadia National Park. 

Mount Washington was first explored by colonists in 1642, but it remained unbothered for nearly another century. The famous hotel there was built between 1900–02 but didn't have its first winter season until 1999. 

It's all about sustainability at Shelburne Farms in Vermont—from school field trips to teachers' continuing education courses. The farm holds programs about historic preservation, natural resources, and naturally, farming practices.

The Fox Theater isn't your run-of-the-mill cinema chain. When it opened in 1928 it had the second largest seating capacity in the world and seats more than 5,000. Of "movie palaces" of the era, it's now the largest surviving.

Why is a cemetery on a list of must-sees? History and beauty, of course. It has 450 acres developed of 733. There are lakes, islands, footbridges, and protected wooded areas just ripe for a peaceful stroll. It was chartered in 1845.

People have been touring Mammoth Cave for 200 years. The cave system along the Green River Valley is the world's longest.

Another luxurious historic hotel is on this road trip list. Besides having an atrium that's a feast for the eyes, the West Baden Springs Hotel hosts special events, entertainment, and historic tours, for those staying or not.

Former President Lincoln's home first opened for tours in 1887. If you've seen Washington's home and the White House (also on this list), you can't ignore Lincoln's!

No, you don't have to take the stairs. The Gateway Arch's tram will take you to the top for some incredible 360-degree views.

The 1913 carousel has been restored by volunteers and first ran again in 2005 after being purchased in 1997. There are also the Liberty Carousel and a Primitive Carousel, from the mid-1800s. 

Tours in the Iowa governor's mansion are available seasonally; it also hosts special events such as the "Tea & Talk" series and the annual garden party and the ​piano competition. 

Step into a time capsule and see what made Frank Lloyd Wright's homes so influential and distinctive. 

If you're interested in the history of this country, the tension between the new arrivals and the folks already here affected it for centuries. Fort Snelling is located near the Mississippi and the state's cemetery for its veterans and is just a few train stops from the Mall of America. 

More than 200 fossil skeletons have been recovered from a pit in Nebraska. You need no other reason to go and see the Ashfall Fossil Beds.

It was a massive feat of engineering that extended over decades to carve the presidents' heads into a granite bluff at Mount Rushmore. The drama and politics behind its construction are just as fascinating. Just down the road is Crazy Horse, which is still under construction and also has been for decades. Don't miss either one.

Built in a region where 10 Northern Plains Tribes lived, the Fort Union Trading Post was the most important post in the Upper Missouri region until smallpox decimated the people there.

You can't put a boat in waters there because of the invasive zebra mussels, but there's still much beauty to enjoy in Glacier National Park. 

Yep, on this road trip, you can even explore cleanup of a former nuclear site, which has been going on for three decades, but you'll want to confirm the dates for public tours in advance. 

Lots of hiking, biking, and walking opportunities exist on the Columbia River Highway, and portions of the old road are being turned into trails.

Ride a streetcar (probably not named Desire) in the place where they were invented, San Francisco, and scratch another iconic activity off your U.S. travel to-do list.

Many sections of the San Andreas Fault are easy to visit because they reside in National Parks, National Forests, or on Bureau of Land Management Land.

Want to be in two time zones at once? You can be as you walk across Hoover Dam. If that's not enough of a thrill, there are also tours of the power plant and dam as well.