This is a volcanic ridge.

But 10 miles down the ridge...

The climbers got on the southeast ridge.

Is this the bus for Park Ridge?

And there were climbers on that summit ridge.

This is the view looking at the southeast ridge.

This is a view taken along the summit ridge.

39 percent of homes on Pine Ridge have no electricity.

We worry about cocaine coming from the Andean Ridge north.

OK, this is a view taken on the summit ridge itself.

The mid ocean ridge runs around like the seam on a baseball.

This is all you've got. You're very exposed on the summit ridge.

Unemployment on the Pine Ridge Indian Reservation fluctuates between 85 and 90 percent.

This is what a real one looks like, on the Juan de Fuca Ridge.

We're going to look at the mid ocean ridge, a 40,000 mile long mountain range.

Both Denmark and Russia have been devoting significant resources to exploring the Lomonosov Ridge. Denmark has hired Swedish icebreakers for repeated expeditions, and Russia has been deploying special submarines to obtain samples from the ridge and the ocean floor.

Her name is Pam Moran in Albemarle County, Virginia, the foothills of the Blue Ridge Mountains.

The tuberculosis rate on Pine Ridge is approximately eight times higher than the U.S. national average.

Narrow national mindsets are counterproductive.

Because it's along the axis of the mid ocean ridge where the great crustal plates are separating.

What looks like a cloud behind the summit ridge is actually snow being blown off the summit.

The mid ocean ridge is a huge mountain range, 40,000 miles long, snaking around the entire globe.

Step by step, it does narrow.

The angle would be too narrow.

There's narrow road to the village.

How to assess countries claims to Arctic territory hinges on the status of the Lomonosov Ridge, a vast formation that rises from the sea floor and stretches 1,800 kilometers from Greenland to the East Siberian continental shelf. Everyone agrees that it is a ridge.

The road is too narrow for cars.

The road is too narrow for cars.

The man is hiking on a narrow path.

This is a clear but very narrow standard.

And the climbers up on the ridge were that much higher, 2,000 feet higher, and completely exposed to the elements.

So let me narrow the choices down to two.

Plastics have overlapping densities over a very narrow range.

This road is too narrow for cars to pass.

The straits were too narrow for the cruise ship.

States parties to the Treaty must narrow that gap.

Todd and Pete got up to the summit ridge, up in here, and it was a scene of complete chaos up there.

And for the house he made windows of narrow lights.

And for the house he made windows of narrow lights.

The donor base for these contributions has remained relatively narrow.

The Pine Ridge Reservation, the subject of today's slide show, is located about 75 miles southeast of the Black Hills in South Dakota.

And this kind of life and death of hydrothermal vent communities is going on every 30 or 40 years all along the ridge.

The ground handicap must not be confined within a narrow definition.

That would narrow the gap between these countries and developed ones.

There's a ridge right in the middle of the picture, up above where that arrow comes in, that shows you that a little bit.