Awesome Limestone Caves

The great size and beauty of limestone caves have made them features of public amazement and wonder. More than 130 caves in the United States are open commercially, and at least 13 national parks and monuments contain caves. The world's longest cave appears to be Kentucky's Mammoth Cave which has more than 240 kilometers (150 miles) of accessible passages. The largest subterranean chamber yet discovered is the Big Room of New Mexico's Carlsbad Caverns. The Big Room is about 400 meters (1,312 feet) long, 200 meters (656 feet) wide, 90 meters (295 feet) high, and contains the Great Dome, a stalagmite 19 meters (62 feet) tall. Gouffre Berger Cave near Grenoble, France, descends at least 1,100 meters (3,680 feet) below the surface and is the deepest cave yet explored by man. Records of the National Speleological Society of America indicate more than 11,000 caves in the United States, and it appears likely that 100,000 caves exist in the whole earth.

 

Amazzing Earth

1. Caldera of Mount Katmai, in Alaska

Mount Katmai is a large stratovolcano (composite volcano) on the Alaska Peninsula in southern Alaska, located within Katmai National Park and Preserve. It is about 6.3 miles (10 km) in diameter with a central lake-filled caldera about 3 by 2 mi (4.5 by 3 km) in area, formed during the Novarupta eruption of 1912. The caldera rim reaches a maximum elevation of 6,716 feet (2,047 m). In 1975 the surface of the crater lake was at an elevation of about 4,220 feet (1,286 m), and the estimated elevation of the caldera floor is about 3,400 ft (1,040 m). The mountain is located in Kodiak Island Borough, very close to its border with Lake and Peninsula Borough.

2. GRAND PRISMATIC SPRING – YELLOWSTONE NATIONAL PARK, WYOMING

 

The Grand Prismatic Spring in Yellowstone National Park is the largest hot spring in the United States, and the third largest in the world, after Frying Pan Lake in New Zealand and Boiling Lake in Dominica. It is located in the Midway Geyser Basin.
Grand Prismatic Spring was noted by geologists working in the Hayden Geological Survey of 1871, and named by them for its striking coloration. Its colors include blue, green, yellow, orange, gold, red and brown, and recall the rainbow dispersion of white light by an optical prism.

3. Igauazu Falls

Iguazu Falls are waterfalls of the Iguazu River on the border of Brazilian state Paraná and Argentine province Misiones. The falls divide the river into the upper and lower Iguazu. The Iguazu River rises near the city of Curitiba. It flows through Brazil for most of its course. Below its confluence with the San Antonio River, the Iguazu River forms the boundary between Argentina and Brazil. 

4. Angel Falls 

Angel Falls is a waterfall in Venezuela. It is the world's highest uninterrupted waterfall, with a height of 979 m (3,212 ft) and a plunge of 807 m (2,648 ft). The waterfall drops over the edge of the Auyantepui mountain in the Canaima National Park (Spanish: Parque Nacional Canaima), a UNESCO World Heritage site in the Gran Sabana region of Bolívar State. The height figure 979 m (3,212 ft) mostly consists of the main plunge but also includes about 400 m (0.25 mi) of sloped cascades and rapids below the drop and a 30-metre (98 ft) high plunge downstream of the talus rapids.

5. Northern Lights - Aurora Borealis

  

The Northern Lights exist in the outmost layer of the atmosphere. They are created by electrically charged particles that make the thin air shine, not unlike a fluorescent light. They can be seen in auroral belts that forms 20-25 degrees around the geomagnetic poles, both the north and the south. The Northern Lights, also called Aurora Borealis are one of the most spectacular shows on this earth and can frequently be seen in Iceland from September through April on clear and crisp nights. The Northern Lights occur high above the surface of the earth where the atmosphere has become extremely thin, in an altitude of 100-250km.