He says the substances are especially dangerous because they travel through the air and stay in the atmosphere, soil and water.

VOA: special.2009.06.23

Andrew and Samantha are trying to get back to safety in the United States but they have to travel through the so-called infected area in Mexico.

VOA: special.2010.10.29

Victor Weisskopf's suggestion resulted in an explanation of how electrons travel through semiconductors.

VOA: special.2010.11.09

The campsite moves with you as you travel through the park.

VOA: special.2009.08.19

It was not possible to travel straight through because of the Rocky Mountains and the deep snow that fell in winter.

VOA: special.2010.04.26

The only passenger on that first stage to travel all the way through to San Francisco was a newspaper reporter named Waterman Ormsby.

VOA: special.2010.04.26

The blue light is the product of a long travel path through the snow or ice.

VOA: special.2010.01.05

"We will use the tremendous capabilities of this ion propulsion system to climb out of orbit around Vesta, travel for almost another three years through the asteroid belt to dwarf planet Ceres and then go into orbit around Ceres and undertake the same kind of measurements there that we'll be doing at Vesta.

VOA: special.2011.07.27