Tennessee is known for many great things, but not for its abundance of water features or beaches. However, there's one spectacular spot in the state that has crystal blue water. This popular Tennessee attraction is over a hundred feet underground and visitors can actually explore it.

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The Lost Sea in Sweetwater, Tennessee is a gem that needs to be visited. This spot is America's largest underground lake and Registered National Landmark, according to the official website. 

Visitors can take a tour every single day of the year, with the exception of Thanksgiving and Christmas Day. There are so many things to do and see that it'll be easy for visitors to spend an entire day here.

The caverns are part of a historic cave system called the Craighead Caverns. They've been used for hundreds of years and a plethora of Cherokee artifacts have even been found throughout the caverns.

The tours start with a simple guided walkthrough in the actual caverns before visitors descend 140 feet underground for the boat excursion.

The walking tour is about a quarter of a mile long and the guides will talk about the history and the geological aspects of the cave. 

This lake covers more than four acres underground and is a crisp 58 degrees at all times. The boat will go through various rooms of the caverns and guests will be able to see "cave flowers" and various rock formations

There's also a general store, an ice cream parlor, a cafe, a gem mine and even a glassblower guests can experience during their visit.

"We had such a fun morning exploring the cave and the Lost Sea! We drove about 45 minutes out of the way to get there and it was well worth the travel time to visit America's largest underground lake," writes one Yelp reviewer. "I had a lot of favorite moments and highlights on this tour but I don't want to spoil it all for you. Just know you will enjoy it!"

If that's not enough to feed your adventurous soul, there's a trail on the property that's only about a third of a mile — ready to be explored.

The Lost Sea 

Price: $22.95

Address: 140 Lost Sea Rd., Sweetwater, TN

Why You Need To Go: This adventure will take you 140 feet underground to various cavern rooms and on a boat ride adventure over a blue lake.