tán is underlaid with subterranean sinkholes called cenotes,
and the Maya dug wells to reach the freshwater contained in
these. Lack of water and hilly terrain forced people to build
rainwater reservoirs, construct irrigation systems, and dig
terraces on hillsides for their crops. Historians believe that
rainfall fl uctuated in the area during the ancient period.
From 5500 to 500 b.c.e. the region was relatively wet, fol-
lowed by about 250 years of drought. Th e Classic Maya civili-
zation arose during another period of high rainfall between
250 b.c.e. and 125 c.e. Another drought between 125 and
250 c.e. led the Maya to abandon some of their settlements,
such as El Mirador. Large portions of the Maya population
died out during dry periods, only to be built back up when
the rains returned.
Th e Maya who lived in this region became very skilled
at maximizing their use of available water. In much of the
southern Yucatán the ground is made of porous limestone;
water runs straight through the rock into the ground here,
and people could not make use of it for crops. In this area
people dug holes in the limestone and plastered their bottoms
to create artifi cial reservoirs. Even during wet times Maya
faced food problems; the humid climate made it diffi cult to
store corn for any length of time, so they could never build
up a surplus of food to stave off famine in years of bad har-
vests. Th roughout the region people lived in small city-states
positioned on watersheds, which gave them the fl exibility to
handle sudden droughts.
South of the Yucatán the mountains continue through
modern Guatemala, Honduras, and northwestern Nicara-
gua. Th e distance between the Pacifi c and the Caribbean Sea
is narrower here than in Mexico. A number of rivers fl ow
through this area, and it has several large lakes, notably Lago
de Nicaragua. Th is region was covered with forests in ancient
times. It is wetter than Mexico; the coastal regions have a wet,
tropical climate, though the highlands are cooler and drier.
Most rain falls between April and October. Hurricanes have
always been a danger here.
From modern Costa Rica to the point where modern
Panama joins northern Colombia the land forms a narrow
S-shaped pattern. In this region the Pacifi c coast lies to the
south of the land, and the Caribbean Sea lies to the north. Th e
mountains continue to run down the center of the isthmus
with swampy lowlands on the coasts. Th e climate is warm
and wet. Th e climate and the range of habitats made this re-
gion a hospitable home for thousands of species of plants and
animals, many of which were good sources of food.
ANDES AND WESTERN SOUTH AMERICA
Th e Andes Mountains run the entire length of the western
coast of South America. Th e name Andes comes from a Que-
chua (a local Indian language) word meaning “high crest.”
At 4,400 miles long, the Andes chain is the longest moun-
tain range in the world. Th e Andes are the second-highest
mountain chain, aft er the Himalayas; Mount Aconcagua
(22,841 feet) in modern Argentina is the highest mountain
in the Americas. Th e Andes range is about 150 to 200 miles
wide along most of its length, except in Bolivia, where it is
about 400 miles wide. Most of the tallest peaks are covered
with snow year-round. Th e snow line varies from north to
south. Th e southernmost peaks have very low snow lines
and permanent glaciers. Th e snow line in the central Andes
of Chile and Peru is actually higher than that of the tropi-
cal Andes; the wetter climate in the north allows for more
snow to fall.
Th e Andes harbor several active volcanoes. Th e most
famous is Cotopaxi, which assumed its current shape about
3000 b.c.e. Th is geothermal activity heats underground wa-
ter, which comes above ground in numerous hot springs. Th e
Galapagos Islands, about 1,000 miles west of Peru on the
equator, were also formed by volcanic activity.
Th e Andes in the north begin in Colombia, Venezuela,
and Ecuador. In this area they exist as two parallel mountain
ranges, currently called the Cordillera Occidental (Western
Rope) and the Cordillera Oriental (Eastern Rope). Th e Carib-
bean Islands of Aruba, Bonaire, and Curaçao are actually part
of the range, with most of their landmass submerged. Two
branches of the chain border either side of Lake Maracaibo.
Th e Maracaibo lowlands of western Venezuela are fl at and
swampy and have never attracted much human settlement.
Th e Central Andes lie in modern Peru, Chile, and Bolivia.
Th e snow line begins at about 15,700 feet. Th e western portion
of the mountain range is quite dry, though the eastern moun-
tains toward the Amazon region receive fairly heavy rainfall,
over 100 inches a year in modern times. A fl at coastal plain
lies between the western mountains and the Pacifi c Ocean.
Th e climate here is normally very dry but is greatly aff ected
by periodic El Niño events, which can cause large amounts to
fall all at once. At high elevations temperatures do not vary
much over the course of the year but can change drastically
from day to night, dropping from 75 degrees Fahrenheit to
32 degrees Fahrenheit in a matter of hours. Rivers on the east
side of the Andes drain into the Amazon, and rivers on the
west drain into the Pacifi c. Lake Titicaca, one of the highest
lakes in the world, lies in the Andes on the modern border
between Peru and Bolivia.
Between 1500 b.c.e. and 500 c.e., the Lake Titicaca re-
gion had higher rainfall than it does now. Between 300 and
500 c.e. Lake Titicaca was higher than today, making agricul-
ture easier. Th e area around Lake Titicaca was a fruitful habi-
tat for the people of Tiwanaku, a civilization that fl ourished
in southern Peru and northwest Bolivia starting around 400
b.c.e.; by 650 c.e. it had a large population. Rainfall was un-
predictable, so the people of the region used the fl uctuating
waters of Lake Titicaca to water crops in raised fi elds. A cen-
tralized bureaucracy helped the people organize themselves
enough to cope with the harsh climate. Th e Tiwanaku civi-
lization eventually died out during a major drought starting
around 1000 c.e.climate and geography: The Americas 267