walls had to become stronger. In 1885
William Le Baron Jenney designed the
Home Insurance Company Building in
Chicago, Illinois. It was the first building
in which the exterior walls were
entirely supported on an internal steel
frame. The steel frame led to the skyscraper
age.
One of the most influential architects of
the skyscraper was Chicagos Louis Sullivan.
He believed that a buildings design
should reflect its function, and he often
used decoration based on natural forms.
His student Frank LloydWright became
one of the most influential architects of
the 1900s. He thought buildings should
be in harmony with their natural surroundings
and the people who use them.
The clean, simple lines of modernist
architecture are shown in
buildings designed by Mies van
der Rohe.
BRITANNICA STUDENT ENCYCLOPEDIA Architecture 171
His Prairie style emphasized horizontal
lines in houses with low, gently sloping
roofs.
Modernist buildings of the mid-1900s
typically had plain, rectangular forms
with no extra decoration. The architect
known as Le Corbusier designed buildings
in France with flowing interior
spaces, flat roofs, and large windows in
plain white walls. German architect
Ludwig Mies van der Rohe designed
steel and glass structures in simple geometric
forms with clean lines.
Beginning in the 1960s some architects
reacted against what they saw as the
cold, bare forms of modernism. These
architects were called postmodern. They
included Philip Johnson, Robert
Venturi, and Michael Graves. Some of
them playfully used classical features
such as arches and columns in new
ways. Starting in the late 20th century
architects such as Frank Gehry moved
away from traditional right angles. They
featured free-form curves in many of
their designs.
#More to explore
Acropolis Brick and Tile Cathedral
Concrete Church Egypt, Ancient
Greece, Ancient Iron Middle Ages
Mosque Pyramid Renaissance
Skyscraper Steel Taj Mahal
Temple
Arctic Ocean
The Arctic is the smallest of the worlds
oceans. It occupies the most northern
region of Earth. The North Pole is near
the center of the Arctic Ocean.
Physical Features
The Arctic Ocean covers an area of
5,440,000 square miles (14,090,000
square kilometers). The landmasses of
Eurasia (Europe and Asia), North
America, and Greenland surround the
ocean. The Arctic has several islands on
its edges but none in the center, where
there is a permanent cover of ice. A
narrow passage called the Bering Strait
connects the Arctic Ocean with the
Pacific Ocean. The Greenland Sea
connects the Arctic with the Atlantic
The MARTa museum in Germany was
designed by Frank Gehry.
172 Arctic Ocean BRITANNICA STUDENT ENCYCLOPEDIA
Ocean. The deepest point in Arctic
waters is 18,050 feet (5,502 meters),
but the average depth is 3,240 feet (988
meters).
Two forms of ice are found in the
Arctic Ocean: sea ice and pack ice. Sea
ice is frozen seawater that forms and
melts depending on the season. The
mass of sea ice that remains frozen year
after year is called pack ice. Pack ice is
generally smoother and less salty than
other sea ice.
The pack ice in the Arctic is hundreds of
miles across. It drifts around the ocean
in a clockwise direction. It completes
one revolution around the North Pole
every 10 years.
Climate
All Arctic waters are cold, and the climate
in the Arctic regions is among the
harshest in the world. The coldest temperatures
can drop to .85° F (.65° C),
especially at the end of the long Arctic
winter.
Economy
Because of the ice in the Arctic, there are
very few fish in the main body of the
ocean. However, some of its surrounding
seasthe Barents, Greenland, and
Bering seasare rich fishing grounds.
Whale hunting, or whaling, was once a
major Arctic industry, but governments
now limit it to protect the whales.
People still hunt seals in some areas.
Exploration
The Dutch and the English became the
leaders in Arctic exploration in the early
1500s. They were seeking a route, called
the Northeast Passage, across the Arctic
to the Far East. A Swedish explorer
finally made the trip in 187879. He
sailed from Norway, through the Russian
side of the Arctic Ocean, and out
into the Pacific. In the 1880s and 1890s
Fridtjof Nansen, a Norwegian explorer,
made more important explorations of
the Arctic Ocean.
Later explorers used dog sleds to try to
get across the ice to the North Pole. The
U.S. explorers Robert E. Peary and Matthew
Henson claimed to be the first to
reach the North Pole, in 1909.
Environmental Issues
Hunting in the Arctic has endangered
several types of animals, including
whales and walruses. Other economic
activities are also cause for concern. Oil
tankers that sail through the Arctic
waters are threatened by ice. If damaged,
they can release tons of oil into the
ocean waters.
A walrus sits on top of an iceberg in the
Arctic Ocean.
At the North
Pole the sun
does not rise
above the
horizon for six
months of the
year. For the
rest of the
year the sun
never sets.
BRITANNICA STUDENT ENCYCLOPEDIA Arctic Ocean 173
Global warming may be the most serious
environmental problem for the Arctic
Ocean. Global warming is a slow rise in
Earths temperature that may be caused
by pollution. Some scientists warn that
this warming could cause the Arctic pack
ice to melt. The levels of oceans around
the world would then rise, and many
coastlines would disappear.
#More to explore
GlobalWarming Ocean Polar
Exploration
Ares
In ancient Greek mythology Ares was
the god of war. He was one of the 12
major gods believed to live on Mount
Olympus. His bird was the vulture, and
his animal was the dog. Ares is associated
with Mars, the god of war in
ancient Roman mythology.
Ares was the son of Zeus, the chief god,
and his wife, Hera. Ares was said to have
loved Aphrodite, the goddess of love.
Ares and Aphrodite had several children.
Even though Ares was one of the main
Greek gods, people did not worship him
much. The ancient Greeks thought Ares
was cruel. They believed that he enjoyed
sending war and disease to humans.
Unlike Ares, Mars was a popular and
important god. The Romans thought of
Mars as a powerful nature god, as well as
the god of war. They prayed to him to
protect their crops and farm animals.
The month of March was named after
Mars because it was the time when
farmers began to plant their crops. Mars,
the fourth planet from the sun, was also
named after him.
#More to explore
Aphrodite Mythology
174 Ares BRITANNICA STUDENT ENCYCLOPEDIA
Argentina
The country of Argentina takes up most
of the southern part of South America.
Its name is a Spanish word meaning
Land of Silver, after the silver found
there by Spanish explorers. The capital is
Buenos Aires.
Geography
Argentina is bordered by Chile, Bolivia,
Paraguay, Brazil, and Uruguay. The
Atlantic Ocean lies to the east.
Argentina has four major regions: the
Andes, the North, the Pampas, and Patagonia.