A team of international scientists unlock the secrets of a deadly cave filled with giant crystals. Deep below Mexico lies a mysterious cave packed with extraordinary giant crystals. Among the largest crystals ever found, they have been formed by on of the deadliest environments on the planet. Combining extreme heat with unbearable humidity, without the use of specialised suits and equipment the conditions in the cavern would kill a man within minutes. Yet, despite the danger, scientists are trying to work out exactly how the glittering structures were created. Journey underground with the experts as they embark on a daring mission to try and unlock the secrets of the crystal cave. It looks like Superman's fortress. Hidden deep beneath the surface of the Earth is one of the greatest natural marvels on the planet: a giant crystal cave with crystals up to 36 feet long and weighing 55 tons. But this scorching cavern could kill humans after just 15 minutes of exposure. Follow an international team of scientists as they don high-tech protective gear to safely unlock the secrets of the crystal cave. They'll attempt to answer the questions, What are the crystals made of? How did they reach such superheroic proportions? And is there life here?