Read the text and fill in the gaps with the right phrases.

Russia is the largest country in the world with a total land area of over 17,000,000 square km! It's no surprise that it is full of incredible natural wonders. Some of these places, however, ... , that maybe we shouldn't go there...
The Orda Cave, the Western Urals
Just as Neil Armstrong once reported back from the Moon, a team of daring and experienced cave divers recently got the chance to go where no one had ever been before ... . At temperatures barely above freezing and ... the divers took photographs in order to show people the 3-mile-long underwater wonderland. The unique cave is full of stunning rock structures. Because of the gypsum, a mineral that can form dear crystals, the water was so clear that the divers could see over 45 metres ahead of them! ... that even bubbles from the divers could damage it. Because of this, ... to take their air bubbles safely out of the cave. They hope that now people can see the stunning photographs of the cave, they will understand ... to be protected.