Earth rotates continuously, so different parts of the world face the Sun at different times. Time zones allow countries and regions to use standard clock times suited to their geographical position and administrative needs.

A volcano is an opening or system in Earth’s crust through which molten rock, gases and other materials can reach the surface. Molten rock beneath the surface is called magma; once erupted, it is called lava.

An earthquake is the shaking of the ground caused by a sudden release of energy within Earth. Many earthquakes occur when rocks move along faults associated with tectonic activity.

A glacier is a large, persistent body of land ice formed from accumulated and compacted snow. Under gravity, glacier ice moves slowly and can reshape the landscape.

Caves are natural underground spaces. Many famous cave systems form when slightly acidic groundwater gradually dissolves soluble rocks such as limestone.

Climate describes long-term patterns of temperature, precipitation and other atmospheric conditions. The world can be divided into broad climate regions, although real climate classifications contain many subdivisions.

A canal is a human-made waterway constructed for purposes such as navigation, irrigation, drainage or water supply. Major shipping canals can shorten journeys between seas and oceans.

A harbour is a sheltered area where vessels can anchor or find protection. A port is a place equipped for activities such as loading cargo, handling passengers and supporting ships.

Ancient civilizations developed complex settlements, governments, economic systems, technologies, belief traditions and cultural practices. Several important early civilizations grew near major river systems.

Archaeology studies past human life through material remains such as buildings, tools, pottery, bones, coins and other physical evidence.

Religion has influenced history, philosophy, art, architecture, literature, festivals and community life around the world. Religious traditions contain diverse beliefs and practices, including diversity within each tradition.

Writing systems use visible symbols to represent language. Different systems represent sounds, syllables, words or combinations of linguistic units in different ways.

Traditional clothing can reflect local climate, available materials, occupations, craftsmanship, history, identity, ceremonies and cultural customs.

Cuisine refers to cooking traditions associated with a region or community. Geography, agriculture, trade, migration, religion and history all influence food culture.

Museums collect, conserve, research, interpret and display objects or information of cultural, historical, artistic or scientific importance.

Libraries organise and provide access to information resources. Modern libraries may contain printed books, periodicals, maps, archives, databases, e-books and multimedia resources.

Journalism involves gathering, verifying, reporting and explaining information about events and issues of public interest.

Photography creates images by recording light. Modern digital cameras use electronic image sensors, while traditional film cameras record light on photosensitive film.

Cinema combines moving images, storytelling, performance, sound, music, design and technology. Modern films are created through the work of many specialised teams.

Medicine is the field concerned with maintaining health and preventing, diagnosing and treating illness and injury. It combines scientific knowledge, clinical skills, technology and patient care.

Mathematics studies patterns, quantities, structures, space and change through logical reasoning and symbolic methods. It supports science, engineering, economics, computing and everyday problem solving.

Renewable energy comes from sources that are naturally replenished on human timescales. These sources can reduce dependence on finite fossil fuels and, depending on the technology, lower greenhouse-gas emissions.

Robotics combines computing, electronics and engineering to create machines that can sense their surroundings, process information and perform physical actions.

Bridges carry roads, railways, pedestrians, pipelines or other services across obstacles such as rivers, valleys and roads. Engineers select bridge designs according to span, loads, materials, terrain and environmental conditions.

Skyscrapers are very tall multi-storey buildings. Their construction depends on structural engineering, strong foundations, elevators, fire-safety systems and designs that can respond to forces such as wind.

Railways transport passengers and freight using vehicles that travel along tracks. Rail networks have played a major role in industrial development, trade and the growth of cities.

Aviation includes the design, operation and use of aircraft. Air transport allows passengers and cargo to travel rapidly over long distances.

Maritime transport moves people and goods across oceans, seas, rivers and other navigable waterways. Shipping is especially important for international trade and the movement of large quantities of cargo.

Postal systems organise the collection, sorting, transport and delivery of letters, documents and parcels. Addresses and postal codes help direct mail toward the correct destination.

Measurement compares a physical quantity with an agreed unit. Standard units allow scientists, engineers, businesses and ordinary people to communicate quantities consistently.