The continent of Antarctica has 90% of the world's ice. If the ice melted, many of the world's coastal towns and cities would be submerged by the water.

The GreatBarrier Reef is over 2,000 km long. It is made up of dead and living corals and has taken 600 million years to each its current size.

The Angelfalls in Venezuela are the biggest waterfalls in the world, dropping almost one kilometer to the ground. They were named after an American pilot named Jimmy Angel, who discovered them on November 16, 1933.

PapuaNewGuinea has a small population of about three million people. Yet more than 800 languages are spoken there.

The Universe is everything that exists - matter, space, energy and time. It includes all the stars, planets and other objects in space. But the stars are not scattered haphazardly throughout space, they are found grouped together in huge 'star islands', or Galaxies. 

The sun is the force behind the solar system. If the nuclear furnace at its heart were to go out, it would be ten million years before the effects were felt on Earth. 

A volcano is basically a hole in the Earth through which a fiery mixture of gas, stream, ash and lumps of semi-liquid rock, called lava, are hurled into the air. 

The Earth's crust is essentially made up of substance called minerals. These substances range from rare, phenomenally valuable diamonds to mineral ores that yield the metals we use in everyday life. 

Fossils give us a fascinating glimpse of the many life forms that once existed on Earth. By studying fossils, scientists can learn a great deal about the way in which animals and plant evolved over time. 

Rivers help to shape the landscape. They wash away soil, wear away rocks, and deposit sand, pebbles and boulders downstream. Rivers may even change direction, cutting across curves in their original course and leaving freshwater lakes. 

The air we breathe is part of the atmosphere, the mixture of gases surrounding the Earth. These gases give life to all living things and protect us from harmful sunrays. 

Clouds are masses of airborne water vapor which cover, on avegare, about 50% of the Earth's surface at any one time. They form part of the 'water-cycle' the process which provides life on Earth with fresh water. 

Sailors lost at sea can use clouds to guide them to land. Fleecy clouds on the horizon often form above islands. 

The tallest cloud is Cumulonimbus. It can reach a height of 18 km - twice the height of Mount Everest - and can hold more than half a million tons of water. 

The dividing line between Europe and Asia is generally accepted as being formed by the Ural Mountains, Ural River, Caspian Sea, Caucases Mountains, the Black Sea and through the Bosporus and Dardanelles straits. Beacause of this, part of Turkey lies in Asia while Moscow, the capital of Russia, is in Europe although the greater part of Russia is in Asia. 

Asia is the largest continent and occupies almost one third of the world's land surface. 

The largest lake in the world is the Caspian Sea (371,000 sq km), which is bordered by the countries of Iran, Azerbaijan, Russia, Turkmenistan and Kazakstan. 

The Nile River is the world's longest river at 6,670 km. It flows into the Mediterranean Sea. 

The Sahara is the world's largest desert, spreading over 8 million sq km, and stretching across 12 countries. 

The Andes is the longest mountain chain in the world, extending for about 7,250 km. It stretches from the Panama border to Tierra del Fuego, with a low extension continuing across the ocean to the Antarctic Peninsula. It is rich in minerals, including gold and silver. 

Boyoma Falls in Zaire is the world's greatest waterfalls by volume in cubic meters per second (17,000). 

Guallatiri in Chile is the world's highest volcano at 6,060 m. Lascar (5,990 m) in Chile is the second highest. 

The Saharadesert covers about one third of the total area of Africa.

In Reykjavik, the capital of Iceland, hot water for the town's central heating systems is piped from geysers and hot springs. In icelandic, the word geyser means 'gushing'.

Lake Baikal, in eastern Siberia, is the deepest fresh water lake in the world. It holds over 20% of the world's fresh water.

In the Himalayan mountain range in Nepal is the world's tallest mountain - MountEverest - which is 8,840 meters high. There is a bigger mountain in Hawaii, but most of it is under the sea.

Most volcanoes and earthquakes occur near plate boundaries with most earthquakes being caused by colliding plates. 

There are about 500 active volcanoes in the world. 

The eruption of Mt Vesuvius, Italy, in AD 79 destroyed the town of Pompeii. Mud flows, up to 20 meters thick, covered the nearby town of Herculaneum. 

Coal is formed from dead tree ferns and swamp vegetaion in a process that takes millions of years. 

Petrolium Oil is found trapped in sedimentary rocks. It is produced by the decay of plankton, tiny plants and small animals, probably in anaerobic (airless) conditions. The rocks where it is usually found are rocks such as sandstones or dolomites, which have been folded, and it always accumulates at the tops of folds. 

The first oil well was drilled in Pennsylvannia in 1859, by Colonel EL Drake, who was looking for a source of paraffin wax for making candles. Oil was little used until the 20th century but is now the world's major source of energy. 

The country with has the longest life expectancy is Japan. They have an average life expectancy of 79 years. Japaneses women have the longest life expectancy (82). 

The Pacific Ocean accounts for 32% of the Earth's surface, an area of 166,240,000 sq km. It covers an area greater than that of all the continents put together. Its greatest width from east to west is 16,000 km and its greatest extent from north to south is 11,000 km. 

The name 'Pacific' means peaceful. It was named by explorer Ferdinand Magellan, who sailed across it during 1520-21. 

The Amazon River is the world's largest river basin (7,050,000 sq km). 

To make artificial rain, crystals of silver iodide are shot into clouds from aircraft. Water in the cloud freezes round them, and falls as rain or snow. 

The most consistently wet place is on Kauai in the Hawaiian Islands, USA. Rain falls on average 335 days a year, sometimes as often as 350 days. 

Cloud droplets may remain liquid at temperatures well below 0 Celsius - and may be as low as -15 Celsius. The droplets are then said to be 'supercooled'. 

The colors of the Northern Lights look dazzling against the star-studded blackness of an Alaskan sky. This phenomenon is the result of electrical charging in the ionosphere. 

The driest areas in the world are in norther Chile. In some parts, no rainfall has been recorded for 400 years. 

The Himalayas is the world's most massive mountain range. The peaks average about 6,000 m, with over 90 peaks exceeding 7,000 m. 

The world's largest rainforest is in Brazil and it extends for over 3 million sq km. 

Rainforests contain the greatest variety of plant life in any ecosystem. Over 100 tree varieties can be found in one hectare. 

Soils are formed from fragments of weathered rock and decaying plant debris and contain living organisms. Soils structure is influenced by climate and the vegetation which grows in those climatic conditions. They may also be affected by slope angle or aspect. 

Angel Falls in Venezuela is the world's highest waterfall (979 m).