Large banks of earth and stone built to hold back water. Similar to levees, but to prevent ocean waters from flooding coasts that are under sea level.

Lands reclaimed from the sea in the Netherlands, once drained and kept dry by the use of windmills.

Strong northerly winds from the Alps that can bring cold air to southern France.

Dry winter winds that blow down from mountains into valleys and plains, melting snow and triggering avalanches.

A large mass of ice, snow and rock that slides down a mountainside.

Beginning in the 1700s, the rapid, major change in the economy with the introduction of power-driven machinery.

An economic system in which business leaders use profits to expand their companies.

A theory that calls for economic equality and ownership of resources and factories by the state.

The mass murder of 6 million Jewish people by Germany's Nazi regime during World War II.

The power struggle between the Soviet Union and the United States after World War II.

The transfer of power and responsibility from the federal government to local and regional authorities.

A foreign laborer living and working temporarily in another country.

An industry based on huge farms that rely on machines and mass-production methods.

An international organization of European countries formed after World War II to reduce trade barriers and increase cooperation among its members.

Rain or any other form of precipitation that is unusually acidic, meaning that it has elevated levels of hydrogen ions. It can have harmful effects on plants, aquatic animals, and infrastructure.

An amendment to the international treaty on climate change designed to reduce the amount of greenhouse gases emitted by specific countries

A method for managing pollution in which a limit is placed on emissions, while businesses and countries can buy and sell emission allowances.

A series of religious wars between Christians and the Islamic states of the eastern Mediterranean for control of the Holy Land. Europeans did not win permanent control of the region, but they did open trade routes, resulting in the exchange of cultural ideas, economics and politics between Europe and Southwest Asia.

Religious movement beginning in 1519, resulting in the split of the Roman Catholic Church and the formation of several new Christian denominations.