1. Glacial Grooves State Memorial (Kelleys Island)
Few people are aware that Ohio is home to the largest accessible glacial grooves in the world. You can find them on Kelleys Island, and they’re a must-see if you get a chance to travel to the Lake Erie Islands. Measuring 400 feet long, 35 feet wide and 15 feet deep, the Glacial Grooves State Memorial attracts visitors from around the world. Today, you can explore the grooves from different perspectives via a winding series of steps and footbridges that loop around the upper rim of them. You'll find them at 739 Division St., Kelleys Island, OH 43438.
2. Brandywine Falls (Sagamore Hills Township)
Cuyahoga Valley National Park in northeast Ohio is home to a breathtaking 65-foot waterfall that flows from Brandywine Creek. If you’d rather not take the 1.75-mile hike to the falls, you can drive to the upper and lower boardwalks, which are located just off of Brandywine Road. (A boardwalk option without stairs is also available.) You'll find the falls at 8176 Brandywine Road in Sagamore Hills Township.
3. Crystal Cave (Put-In-Bay)
Crystal Cave on South Bass Island is a hidden gem that most people don’t about. Imagine a cave of nothing but celestine crystals. Pretty cool, right? In fact, Crystal Cave is the largest known geode in the whole world—and it’s right here in the Buckeye State. Discovered in 1897 while digging a well for a winery, Crystal Cave is 35 feet below the surface and about 12,000-15,000 years old. Today, it's part of the winery and you can find it at 978 Catawba Ave., Put-In-Bay, OH 43456.
4. Great Serpent Mound (Peebles)
This 1,348-foot-long and three-foot-high prehistoric effigy mound along Ohio Brush Creek in Adams County continues to marvel locals and visitors alike. It is one of the most impressive earthworks in North America, constructed in the shape of a snake. It was built around 1000 A.D. by the Fort Ancient culture and likely used as a place of ceremony. You'll find Great Serpent Mound at 3850 OH-73, Peebles, OH 45660.
5. Ohio Caverns (West Liberty)
"America's Most Colorful Caverns" can be found in West Liberty, Ohio. The caverns were formed thousands of years ago when an underground river cut through ancient limestone and created vast rooms and passageways. These passageways are now filled with crystal stalactites, stalagmites and many other formations. Within the Ohio Caverns is one of the world's largest and most perfectly formed stalactites. Crystal King is nearly five feet long, weighing an estimated 400 pounds, and is estimated to be more than 200,000 years old. Ohio Caverns is located at 2210 State Route 245 East, West Liberty, OH 43357.
6. Paine Falls (Painesville)
Painesville is home to this two-tiered waterfall, which is easy to visit. (It's especially impressive after heavy rainfall.) Paine Falls Metropolitan Park is located at 5570 Paine Rd., Painesville, OH 44077.
7. Olentangy Indian Caverns (Delaware)
A trip to Olentangy Indian Caverns in Delaware, Ohio is an adventure the whole family will love. Mine for gems, explore ancient caverns and more at this little-known destination. Formed by an underground river cutting through solid limestone rock, these caverns were formed millions of years ago, making them an exciting natural wonder to explore. You'll find them at 1779 Home Rd., Delaware, OH 43015.
8. Hayden Falls (Dublin)
Hayden Falls Park in Dublin features a truly unique natural ecosystem, rare plants and animals and a 35-foot waterfall along the western shore of the Scioto River. It is located at 4326 Hayden Run Rd., Dublin, OH 43017.
9. Seneca Caverns (Bellevue)
Located in Bellevue, Ohio is another geographical wonder that was first discovered in 1872. When you venture to these caverns you will travel through "The Earth Crack" and view the Ole' Mist'ry River. You'll find Seneca Caverns at 15248 E Township Rd., 178, Bellevue, OH 44811.
Did you know about all of these? What other natural wonders are there in Ohio hiding in plain sight? Share your thoughts, photos and experiences with us!