Tour these sites, which have been nominated to the UNESCO World Heritage List.

At face value, going to see a large mound of dirt seems far from extraordinary. But when that mound of dirt was built more than 2,000 years ago in precise astrological alignment, surrounded by perfectly geometric walls, a mystery emerges.

From about 200 B.C. to 400 A.D., the Native American Hopewell culture inhabited regions of Southern Ohio. Evidence of their existence continues to emerge through studying the earthworks—large banks of soil—built by these people. Today, remnants and restored parts of these original structures can be seen in Ross, Licking and Warren counties, among others.

Three of these sites in Ohio—together known as the Hopewell Ceremonial Earthworks—have been nominated to the UNESCO World Heritage List, which includes 1,073 locations throughout the world with particular cultural or physical significance. If approved, they will join such well-known sites as the Taj Mahal, Machu Picchu and the Grand Canyon.

The purpose of these earthworks remains somewhat of a mystery, though it is believed that burials, feasts and rites of passage took place in these spaces. Many earthworks align with solar and lunar events, with a precision indicative of a religion tied to astronomy and the cosmos.

“It's really remarkable that so many of these earthworks survived until today,” said Jen Aultman, World Heritage Project coordinator for the Ohio History Connection. “They didn't just erode away. That's because [the Hopewell culture was] really good at building with earth.”

Here's a look at each of the nominated sites, all of which are—to some extent—open to visitors.

Hopewell Culture National Historical Park

16062 State Route 104, Chillicothe

740-774-1126

nps.gov/hocu/index.htm

The Hopewell Culture National Historical Park in Ross County is composed of six sites, five of which are nominated for the World Heritage List. The National Park Service property encompasses nearly 1,800 acres. Each site offers a different perspective into the Hopewell people.

Park ranger Susan Knisley recommends starting at the Mound City Group visitor center. The Mound City Group of earthworks is the only fully restored site in the park. Visitors can walk the trail, which is less than a mile long, and see almost two dozen mounds in what was one a sacred space for the Hopewell culture. Tours are offered daily from Memorial Day through Labor Day.

Children can take free art classes during the summer, and free Junior Archaeology days are scheduled periodically throughout the summer and fall. Advance registration is required for both. A daily self-guided Junior Ranger program allows kids to receive a badge and certificate for completing a booklet and quiz, available online or at the visitor center.

Three of the five other Mound City locations also are open to the public: Hopeton Earthworks, Hopewell Mound Group and Seip Earthworks. These sites are all self-guided, but Mound City park rangers are available to offer directions and interpretations.

The Hopeton Earthworks are about a mile east of the Mound City Group. A 1.1-mile trail leads visitors to an overlook to view the earthwork remnants. The site originally featured a large circle intersecting a large square earthwork and served as a ceremonial gathering site. There are picnic areas but no public restrooms.

At the Hopewell Mound Group, a 2.5-mile interpretive trail leads visitors through the remains of more than two dozen burial sites within geometrically shaped enclosures. The location also houses a picnic area and restrooms.

More than two miles of walls stretching as high as 10 feet used to stand at the Seip Earthworks. Today, visitors can see a reconstructed mound and parts of the reconstructed wall. The site has a portable restroom and a public picnic area.

High Bank Works, a site for archaeological research, is not open to the public.

The site not nominated for the World Heritage List, Spruce Hill Earthworks, isn't available for daily visitation, but visitors can obtain a permit to visit the plateaued earthwork. Be aware that the hike to the top is relatively difficult, and there are no public restrooms or visitor facilities.

The areas within Hopewell Culture National Historical Park are spread out from one another, so be sure to factor in driving time if attempting to visit all of the publicly accessible sites. Admission is free. Park grounds at the Mound City Group, Hopeton Earthworks, Hopewell Mound Group and Seip Earthworks are open from dawn to dusk.

Newark Earthworks State Memorial

455 Hebron Road, Heath

740-344-0498

ohiohistory.org/visit/museum-and-site-locator/newark-earthworks

The Newark Earthworks State Memorial in Licking County showcases geometric structures built by the Hopewell culture. The entire site encompasses about 4.5 square miles.

One of the sacred sights here is the Octagon Earthworks, which originally boasted 550-foot-long walls up to 6 feet high. Interim site manager Tim Jordan estimated that more than half of the site mirrors the original earthwork. Only the exterior is accessible to the public because Moundbuilders Country Club owns much of the site.

Four times throughout the year, Moundbuilders opens its grounds for an Octagon Earthworks open house, whose final 2018 date was Oct. 7. Visitors can see the interior of the earthwork, take tours, visit information booths and participate in hands-on activities suitable for children, Jordan said.

Just as the name suggests, the Great Circle Earthworks consist of 8-foot-tall walls creating a circle almost 1,200 feet in diameter. It was most likely used as a ceremonial center. Jordan estimated this earthwork to be about 90 percent original.

The Great Circle Museum explains more about earthworks as well as the history of the Hopewell culture. The museum is open from noon to 4 p.m. Fridays to Sundays between January and Memorial Day, Wednesdays to Sundays from Memorial Day to October, and closed in November, December and on major holidays.

On Saturdays in September and October, the park offers free, 45-minute guided tours of the Great Circle, starting at 2 p.m., and the publicly accessible portions of the Octagon, starting at 4:15 p.m. Groups can schedule weekday tours for a fee.

Finally, the Wright Earthworks include fragments of a nearly perfect geometric square enclosure. The sides originally stretched about 950 feet, but farming and construction have reduced one of the walls to less than 200 feet long. There are also remains of an oval earthwork.

All three Newark Earthworks sites are open year-round during daylight hours. Admission is free.

Fort Ancient State Memorial

6123 State Route 350, Oregonia

513-932-4421

fortancient.org/about-us

Fort Ancient is North America's largest ancient hilltop enclosure, found along the Little Miami River. This plateau, which is enclosed by walls ranging from about 5 to 23 feet tall, serves as a reminder of the technological advancements of prehistoric inhabitants of North America.

Due to its elevation, this historic site in Warren County—on the National Register of Historic Places—has remained well-preserved. Mounds originally built 2,000 years ago remain completely visible, said program and volunteer coordinator Pam Hall.

The park has two overlooks that are a short walk from the parking lot, but those feeling more adventurous can explore 2.5 miles of walking trails. There is also an outdoor picnic area.

A museum provides a deeper dive into the Fort Ancient and Hopewell cultures. It includes a large education room where visitors can try on clothes, play drums, step into wigwam huts and more. Children can try atlatl throwing and double ball, common athletic pastimes from this era. A seasonal garden features crops grown by these cultures.

From April to November, the nature preserve is open 10 a.m. to 5 p.m. Tuesdays to Saturdays and noon to 5 p.m. Sundays. From December to March, hours are 10 a.m. to 5 p.m. Saturdays and noon to 5 p.m. Sundays. Admission, which includes the museum, is $7 for adults, $6 for seniors and children ages 6-17, and free for children younger than 6 as well as Ohio History Connection or Dayton Society of National History members. Outdoor admission, without the museum, is $8 per carload and free for members.