White Sands

White Sands National Monument includes the most scenic part of the world's largest gypsum dune field and is located in southern New Mexico. The sand, as white as snow, is composed of fine crystals of gypsum, the same mineral from which plaster of paris is made. The source of the sand is the San Andres Mountains to the west of the basin and the Sacramento Mountains to the east. Both mountain ranges contain massive deposits of gypsum that was formed as an ancient sea evaporated some 100 million years ago. In a process that has gone on for countless centuries, seasonal rains and melting snow carry dissolved gypsum from the mountains down to lake Lucero in the lowest part of the basin.

In this harsh desert environment, the water soon evaporates and leaves a glittering crust of gypsum crystals on the lake bed. Weathering and erosion eventually breaks the crystals into sand-size grains that are carried away by the prevailing winds from the southwest, forming white dunes. The dunes constantly change shape and slowly move downwind, covering the plants in their path. Constantly on the move, the dunes advance upto 33 feet per year.

The gypsum does not readily convert the sun's energy into heat and thus can be walked upon safely with bare feet, even in the hottest summer months. Here and there, however, drought-resistant plants such as salt bush and yucca manage to survive. Here too are found highly specialized pocket mice, lizards, and other creatures whose white coloration makes them nearly invisble on the gleaming gypsum sand.

Giant's Causeway

Giant's Causeway, is an extraordinary grouping of steplike basalt columns some 75 miles across the sea coast on the edge of the Antrim plateau in Northern Ireland. The tops of the columns form stepping stones that lead from the cliff foot and disappear under the sea. Altogether there are 40,000 of these stone columns; some of them have four, five, eight, or even ten sides, but the majority are perfect hexagons ranging from 15 to 20 inches in diameter. Viewed from above, the columns look exactly like paving stones, all neatly fitted into place.
This striking landscape was caused by intense volcanic activity, which brought large amounts of molten basaltic lava to the surface. The molten lava cooled at a slow, very even rate. And as it cooled, the lava gradually contracted, forming prismatic patterns in the cooling rock. As cooling and shrinkage continued, the cracks on the surface extended through the entire lava mass to form a network of vertical joints seperating the flat-sided basaltic columns. Giant's Causeway is a National Natural Reserve, declared a World Heritage site by UNESCO, and is the most popular tourist destination in Northern Ireland. Similar assemblages of basaltic columns are found in many other places, but few can rival the precise geometry of those making up the Giant's Causeway.

Seashells

A shell is a part of a sea creature known as mollusk. Mollusks are wormlike creatures and exist in the ocean, fresh water and also on land. The main characteristic of mollusks is that they dont have internal skeleton. Their shell serves as an exo-skeleton and protects them from the outside world. The shells are primarily composed of calcium carbonate, which is secreted by the outer surface of the mantle of the shell and are loosely attached to the animal body.

The food consumed by mollusk causes pigments to be produced within the mantle and based on this pigment secretion the outer shell's color and shapes are formed. If the pigment secretion is continuous, spiral or radial lines are formed. If the pigment secretion is periodic, then spots appear on the shell. When the mollusk dies, its shell is the one part that typically remains intact. Seashells are very often found in beach drift, which is deposited along strandlines on beaches.

Pamukkale

From a distance the fantastic rock formations of Pamukkale (meaning "cotton castle" in turkish) in southwestern Turkey resemble a castle built of snow and ice. Tier upon tier, the dazzling white ramparts and parapets descend for more than 300 feet down a rugged mountainside. On closer inspection, however, the steplike series of overlapping basins looks more like a gigantic waterfall petrified by some mysterious, awesome force of nature. The strange rocks of Pamukkale are the improbable handiwork of hot springs.

Farther up the mountainside springs bubble from the earth, issuing a stream of water with a temperature of about 43 degree celsius and very high concentration of dissolved mineral salts. The water has been flowing down the slope, cooling, evaporating, and depositing the dissolved minerals. Bit by bit, the walls of the many stepped rocky terraces and basins took their present form. For centuries the spring water has been prized for its therapeutic properties. In ancient times the Romans built a thermal resort, Hierapolis, nearby.

Strokkur

Ever since medieval times, Iceland has been famous for its many hot springs and geysers. Although the Geysir's performance has become less impressive in recent times, dozens of other hot springs continue to bubble and spurt in the same thermal area in southwestern Iceland. Amoung the most active and predictable in the group, located in a valley at the foot of a range of volcanic mountains, is Strokkur, the "churn". Every 4 to 10 minutes it shoots a jet of boiling water as high as 100 feet into the sky.

Fluctuations in the water level in its basin herald each eruption. As the turbulence increases, the surface of the water heaves up into a dome, then explodes into a cloumn of steam and water droplets. The clouds of vapour blow away on the breeze, but the water falls back to the basin to contribute to the next eruption. The abundance of geysers is due to Iceland's geological history. In this volcanically active zone, molten magama lies close to the earth's surface, where it heats underground water and powers its periodic eruptive escapes through fissures in the crust.

Eisriesenwelt

The mysteries of Eisriesenwelt were not discovered until 1879. Subsequent exploration revealed that the cave system extends over a total distance of some 26 miles (42 Kilometers). Eisriesenwelt - the "world of the ice giants" - is the largest ice cave in the world. Much of the interior of this cave system high in the Austrian Alps is filled with the fanciful forms of stalactites and stalagmites similar to those found in other caves. But here the contours seem to be more fluid and the colors more translucent. The reason is: The underground formations are composed not of minerals but of ice.
 
Since the temperature in the cave remains at or near freezing all year round, water dripping from the ceiling solidifies into immense icicles, similar to stalactites. Drops falling to the floor freeze, to form spirelike stalagmites. In some places ice stalactites and stalagmites have joined into large floor-to-ceiling fluted pillars. Currently about 200,000 tourists come here every year. The cave with its entrance perched 3,300 feet above the valley floor, is accessible by cable car. Beyond the entrance visitors discover an artfully illuminated, shimmering fantasyland of ice sculptures on a mammoth scale.