America's top seven wonders

We will explore the best seven natural wonders of America, the Niagara Falls, the Everglades, the Badlands, the Grand Canyon, the Death Valley, the Alaska’s glaciers and Hawaii’s volcanoes.

Niagara Falls formed about twelve thousand years ago when huge melting sheets of ice formed the Great Lakes. The land was uneven with several drops in level, some very sharp. Water from Lake Erie began to flow north to Lake Ontario as a result of the loss of the ice barrier.

In modern times, several people have gone over Niagara Falls, most of them on purpose. Most also survived. But, we think the beauty and power of Niagara Falls is best experienced from near the water, not in it.
A natural wonder that the United States shares with Canada.

This is the Everglades -- a low, watery, partly coastal area that covers ten thousand square kilometers. The area is filled with sawgrass. This plant grows in sharp, thin pieces that are three to ten meters tall. The Everglades is sometimes called "river of grass."

The area also contains forests of palm, cypress, mangrove and pine. And beautiful plants and sweet-smelling flowers grow in the Everglades. These include several kinds of the highly prized and rare flower, the orchid. Animal species are plentiful. Many colorful birds and butterflies live here. So do snakes, foxes, frogs and even big cats, called Florida panthers. But the Everglades alligators and crocodiles are probably the animals most identified with the Everglades. No other place in the world is home to both.

Once called "the liquid heart" of that state.

These are the Badlands.From the state of South Dakota. Hundreds of thousands of years ago the area was grassland. But, then, forces of nature destroyed the grass. Water and ice cut into the surface of the Earth. They beat at the rocks, wearing them away. The result is one of the world's strangest sights.

All together, the Badlands cover more than fifteen thousand square kilometers. About ten percent is national parkland. The area is a study in extremes. Temperatures in the summer have been as high as forty-six degrees Celsius. In the winter they have dropped to as low as forty-one degrees below zero. Life in the Badlands is difficult. But animals do survive. The most well known is the prairie dog. This small mammal lives in a series of underground passages.

The Grand Canyon is a series of deep long cuts in rock. There are many passages and large raised areas. There are forests on the top level and desert areas down below. They provide support for several different ecosystems. The Colorado River flows through the Grand Canyon. The Canyon offers a lot of information about the physical history of Earth. There is a huge amount of fossil evidence. And its walls provide a record of three of the four major periods of the Earth's geologic time.

During the summer the temperature in Death Valley can reach fifty-seven degrees Celsius. But, it can be dangerously cold in the winter there, too. And storms in the mountains can produce sudden flooding on the valley floor.
Death Valley holds much evidence of nature's past violence. For example, there is Ubehebe Crater. This hole is about one kilometer across and more than two hundred thirty meters deep. It is the remains of a major volcanic explosion about two thousand years ago. Death Valley is an unforgiving place. The heat has killed people in the past. And it will continue to kill those who are not careful in dealing with the area's extreme climate.

These huge, slow-moving masses of ice cover about seventy-five thousand square kilometers.

About one hundred thousand of these rivers of ice flow down mountains. Some start from thousands of meters up a mountain. They can flow to areas just a few hundred meters above sea level. The largest Alaskan glacier is called Malaspina. It is more than two thousand two hundred square kilometers.
Most glaciers move very slowly. But sometimes one will suddenly speed ahead for a year or two. These are called surge-glaciers.

Welcome to Mount Kilauea, the world's most active volcano. It is on the island of Hawaii. Kilauea is not far from Mauna Loa, the largest volcano in the world.
Kilauea has been releasing burning hot liquid rock called lava continuously since nineteen eighty-three. The lava flows down the mountain to the Pacific Ocean. Its fierce heat produces a big cloud of steam when it hits the cold water. Kilauean lava continues to add land to the island. Sometimes visitors are able to walk out near the edge of this new black volcanic rock.