A cave in Texas just underwent a major expansion, and is about to open to the public with an incredible new tour.

The Natural Bridge Caverns, which is located just outside San Antonio, completed an 1,100-foot-long expansion of public passageways, complete with a stainless-steel bridge across the cavern's deepest point and a new viewing area, according to the attraction. The expansion, which will open to the public on May 12, takes guests to areas previously only accessible by cavers.

And with the expansion comes a new tour, Hidden Wonders, which brings visitors to an area of the cave that didn’t have a natural opening to the surface, which the company said allows them to see beautiful formations that grew in a completely sealed environment.

“Our goal is to give visitors a stunning view of the cavern like never before, without impacting its beauty," Brad Wuest, the president of Natural Bridge Caverns, said in a statement. "Developing this tour has been challenging due to many things – including the depth of the new public tour area… We plan to showcase the science behind the beauty of this once hidden cavern on our tour. With Hidden Wonders' many enhancements we have an opportunity to both educate and entertain."

The new tour features a “massive passage” called the Box Canyon, which functions as a “natural theater for a unique sound and light show finale.” The new space also includes a 5,700-square-foot dome chamber, which serves as an event space.

The company also built a 710-foot exit tunnel — carefully constructed for minimal impact on the cavern, according to Natural Bridge Caverns. The project has been in development since 2017.

“We used best in class techniques and developed new ones to make it work,” Wuest said. “We took the time to do it right. The result speaks for itself."

Exploring cave systems is a popular activity across the country with breathtaking caves available to tour in Kentucky, Washington, Tennessee, and more.