Ep 1. Mouth of Hell, The

In "Mouth of Hell, The," the premiere episode of season 11 of National Geographic's Explorer, viewers embark on a thrilling journey through one of the most dangerous cave systems in the world. The episode follows a team of expert cave divers, including renowned explorer Robbie Schmittner and British diver Jill Heinerth, as they venture into the depths of Mexico's Sistema Huautla cave.

With over 38 miles of underground tunnels, the Sistema Huautla cave is the deepest in the western hemisphere and has claimed the lives of several divers over the years. But for Schmittner and Heinerth, exploring this treacherous system is the ultimate challenge.

As the team descends into the dark, labyrinthine passages of the cave, viewers are treated to stunning footage of the underground landscape and the various obstacles that the divers must overcome. From narrow crevices to deep, dark underground lakes, the Sistema Huautla cave presents a daunting test of physical and mental strength.

At the heart of the episode is the team's quest to reach the bottom of the cave system and explore the "Mouth of Hell," a massive chamber that has yet to be fully explored. As they descend deeper into the cave, the team faces numerous challenges, including dangerous currents and lack of oxygen. But with their skill and determination, they are able to push forward, inching closer to their goal with each passing moment.

Along the way, viewers learn about the history and geology of the cave system, as well as the many unique species that call it home. From blind crustaceans to unusual bacteria, the cave is teeming with life despite its inhospitable conditions.

As the team reaches their final destination, the "Mouth of Hell," viewers are treated to a stunning visual spectacle unlike anything they've seen before. With specially-designed equipment, the explorers are able to capture footage of this otherworldly landscape, complete with bizarre formations and hidden chambers.

Overall, "Mouth of Hell, The" is a thrilling and informative episode that showcases the incredible skill and bravery of cave divers and explores one of the most extreme environments on the planet.