32 Tegucigalpa BRITANNICA STUDENT ENCYCLOPEDIA
was the capital of Iran. Tehran was a
suburb of Rayy. Invaders nearly
destroyed Rayy in 1220. Many people
from Rayy then moved to Tehran.
Tehran was the home of several of Iran’s
rulers from the 1500s to the 1700s. It
became the capital of Iran in the 1780s.
Since then it has been the country’s
most important city. In the early 1900s
Iran’s rulers made Tehran larger and
more modern.
During a revolution in 1979 Islamic
leaders took control of Iran. Supporters
of the revolution captured the U.S.
embassy in Tehran. They held a group of
Americans as hostages there from 1979
until 1981.
In the 1980s a long war between Iran
and Iraq hurt Tehran’s economy and
development. In the 1990s the city
began to grow again.
..More to explore
Iran
Tel Aviv–Yafo
Population
(2006
estimate), city,
382,500; urban
area,
3,040,400
Tel Aviv–Yafo is a large city in Israel, a
country in the Middle East. It is Israel’s
main center of business and culture. The
city lies on the Mediterranean Sea. As its
name suggests, it was created by combining
two towns: Tel Aviv and Yafo.
Yafo is the Hebrew name for the ancient
port city of Jaffa.
Most of Israel’s banks and insurance
companies have headquarters in Tel
Aviv–Yafo. Many people in the city
work in business services, tourism, and
trade. Factories in Tel Aviv–Yafo process
diamonds and foods and make clothing,
medicines, and high-technology products.
The bazaar is the market district of Tehran,
Iran. The merchants there offer many types
of goods for sale.
Tel Aviv–Yafo is a modern city on the shore
of the Mediterranean Sea.
BRITANNICA STUDENT ENCYCLOPEDIA Tel Aviv–Yafo 33
Many thousands of years ago Jaffa was a
city of the Canaanite people. It was later
ruled by the Egyptians, Israelites, Persians,
and others. Muslim Arabs ruled
Jaffa from about the 1200s to the
middle of the 1900s.
Jewish settlers founded Tel Aviv in 1906.
At first it was a suburb of Jaffa. At the
time both cities were part of the land
called Palestine. In 1948 part of Palestine,
including Tel Aviv and Jaffa,
became the country of Israel. Israel soon
combined Tel Aviv and Jaffa to create
the city of Tel Aviv–Yafo.
#More to explore
Israel
Telecommunication
Telecommunication is any kind of
human communication that takes place
across a distance. Several inventions have
helped people to communicate quickly
over great distances.
The first important step in telecommunication
was the telegraph. It was
invented in the 1830s by Samuel F.B.
Morse. His invention could send coded
messages instantly over a wire. Long and
short electrical signals, called Morse
Code, stood for letters of the alphabet.
By 1866 telegraph cables under the
Atlantic Ocean linked North America
and Europe.
The telephone made it possible to send
the sound of the human voice over a
wire. Alexander Graham Bell invented
the telephone in 1876. Today telephone
signals may travel through wires,
through fiber-optic cables, or even as
radio waves.
In the 1890s Guglielmo Marconi
invented the wireless telegraph, or radio.
Like the telegraph, his invention sent
messages in code, but the messages traveled
through the air as radio waves. Spoken
messages were first sent by radio in
1907. The first network of radio stations
in the United States was the National
Broadcasting Company (NBC). It
broadcast its first radio programs in
1926.
By the 1930s it was possible to send a
picture as well as a sound signal over
radio waves. This was the beginning of
television (TV). In 1936 the British
Broadcasting Corporation (BBC) started
the world’s first TV programming. Now
television signals may travel as radio
waves or through cables.
Today the Internet makes it possible for
people around the world to communi-
Short-wave, microwave, cellular telephone,
and other types of telecommunication
antennas receive and send messages from
high ground near Phoenix, Arizona.
The historic
section of
Tel Aviv–Yafo
is called Old
Jaffa. It is
known for its
gardens, narrow
alleys,
and art
studios.
34 Telecommunication BRITANNICA STUDENT ENCYCLOPEDIA
cate through computers. The U.S. government
developed an early form of the
Internet in the 1960s and 1970s. Telephone
wires, television cables, fiberoptic
cables, and satellites connect
computers around the world to the
Internet.
#More to explore
Communication • Internet • Radio
• Telegraph • Telephone • Television
Telegraph
The telegraph is a device for communicating
over a distance. It uses electricity
to send coded messages through wires.
In the middle of the 1800s the telegraph
was the fastest way to communicate over
long distances.
Invention of the Telegraph
The first two working telegraphs were
invented at about the same time in the
1830s. In Great Britain two inventors
built a telegraph that used six wires and
five needles. A part called the transmitter
sent electric currents through the
wires. At the other end, the currents
moved needles on a part called the
receiver. The receiver had a special plate
with letters and numbers on it. The
needles pointed to the letters and numbers
to spell out messages.
Meanwhile, in the United States, Samuel
