The best known is "Into Thin Air."

VOA: special.2010.06.30

It includes long,thin,red and white rocks that reach high into the air like fingers on a hand.

VOA: special.2009.04.15

Drop several seeds over the surface of the pot and cover with a thin layer of vermiculite, a substance that can hold air, water and nutrients.

VOA: special.2009.04.21

At about nineteen-thousand meters, the air is so thin and the amount of oxygen so small that a person needs a lot of special equipment to survive.

VOA: special.2011.04.06

The air grew thin within a day.

VOA: special.2010.07.31