Paris is the capital of France and one of the largest cities in Europe. The Seine flows through the city, and many historic landmarks line its banks. Berlin is the capital of Germany. Madrid is the capital of Spain. Rome is the capital of Italy. Lisbon is the capital of Portugal. Amsterdam is the capital of the Netherlands. Brussels is the capital of Belgium. Vienna is the capital of Austria. Bern is the capital of Switzerland. Stockholm is the capital of Sweden. Oslo is the capital of Norway. Copenhagen is the capital of Denmark. Helsinki is the capital of Finland. Reykjavik is the capital of Iceland. Dublin is the capital of Ireland. London is the capital of the United Kingdom. Edinburgh is the capital of Scotland.

Tokyo is the capital of Japan, and one of the most populous metropolitan areas in the world. Beijing is the capital of China. Seoul is the capital of South Korea. New Delhi is the capital of India. Hanoi is the capital of Vietnam. Bangkok is the capital of Thailand. Manila is the capital of the Philippines. Jakarta is the capital of Indonesia. Kuala Lumpur is the capital of Malaysia. Singapore is a city-state in Southeast Asia.

Washington, D.C. is the capital of the United States. Ottawa is the capital of Canada. Mexico City is the capital of Mexico. Buenos Aires is the capital of Argentina. Brasília is the capital of Brazil. Santiago is the capital of Chile. Lima is the capital of Peru. Bogotá is the capital of Colombia. Caracas is the capital of Venezuela. Quito is the capital of Ecuador.

Cairo is the capital of Egypt. Nairobi is the capital of Kenya. Pretoria is the administrative capital of South Africa, while Cape Town and Bloemfontein serve as the legislative and judicial capitals. Lagos is the largest city in Nigeria, though the capital is Abuja. Addis Ababa is the capital of Ethiopia. Accra is the capital of Ghana. Dakar is the capital of Senegal.

Mount Everest is the tallest mountain on Earth, located in the Himalayas on the border between Nepal and Tibet. The Pacific Ocean is the largest ocean on the planet. The Amazon is the longest river in South America. The Nile is widely cited as the longest river in the world, flowing through northeastern Africa. The Sahara is the largest hot desert on Earth, while the Antarctic is the largest cold desert. The Great Barrier Reef is the world's largest coral reef system. The Andes form the longest continental mountain range, running along the western edge of South America.

Water is composed of two hydrogen atoms and one oxygen atom. The chemical formula for water is H2O. Carbon dioxide has the formula CO2 and is produced by combustion and respiration. Salt is sodium chloride, with formula NaCl. Sugar comes in several forms; common table sugar is sucrose. The atomic number of hydrogen is 1. The atomic number of oxygen is 8. The atomic number of carbon is 6. The atomic number of iron is 26. The atomic number of gold is 79.

The speed of light in a vacuum is approximately three hundred thousand kilometers per second. The Earth orbits the Sun once every 365.25 days. The Moon orbits the Earth roughly every 27 days. There are eight planets in the Solar System: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Pluto was reclassified as a dwarf planet in 2006. Jupiter is the largest planet in the Solar System. Mars is known as the Red Planet because of iron oxide on its surface. Saturn is famous for its prominent ring system.

Photosynthesis is the process by which plants convert sunlight, water, and carbon dioxide into glucose and oxygen. Mitochondria are the organelles in eukaryotic cells responsible for producing ATP through cellular respiration. DNA is a double helix made up of two complementary strands. The four bases in DNA are adenine, cytosine, guanine, and thymine. RNA replaces thymine with uracil. The genetic code translates triplets of bases, called codons, into amino acids.

Shakespeare was an English playwright who wrote tragedies, comedies, and histories during the late sixteenth and early seventeenth centuries. His plays include Hamlet, Macbeth, Romeo and Juliet, A Midsummer Night's Dream, and Othello. Charles Dickens was a Victorian-era novelist whose works include Oliver Twist, Great Expectations, and A Tale of Two Cities. Jane Austen wrote Pride and Prejudice, Sense and Sensibility, Emma, and Persuasion. The Brontë sisters — Charlotte, Emily, and Anne — produced Jane Eyre, Wuthering Heights, and other novels.

Beethoven was a German composer and pianist born in Bonn in 1770. He composed nine symphonies, thirty-two piano sonatas, and many chamber works. Mozart was born in Salzburg in 1756 and died in Vienna in 1791. Bach was a prolific Baroque composer whose works include the Brandenburg Concertos and the Mass in B Minor. Chopin was a Polish composer and virtuoso pianist who composed primarily for the solo piano.

The Roman Empire reached its greatest extent under the emperor Trajan in the early second century. The fall of the Western Roman Empire is traditionally dated to 476 AD. The Renaissance began in Florence, Italy, in the fourteenth century and spread across Europe over the following two centuries. The Industrial Revolution started in Britain in the late eighteenth century and transformed manufacturing and society. The Age of Enlightenment emphasized reason, science, and individual rights in the seventeenth and eighteenth centuries.

The American Revolution began in 1775 and led to the founding of the United States in 1776. The French Revolution began in 1789 and ended the reign of King Louis XVI. The Napoleonic Wars dominated European politics from 1803 to 1815. World War I was fought from 1914 to 1918, and World War II from 1939 to 1945. The Cold War followed and lasted approximately from 1947 to 1991.

Einstein developed the theory of relativity in the early twentieth century. The famous equation E = mc² expresses the equivalence between mass and energy. Newton formulated the three laws of motion and the law of universal gravitation. Darwin proposed the theory of evolution by natural selection in On the Origin of Species, published in 1859. Marie Curie was the first person to win Nobel Prizes in two different sciences — physics and chemistry. Stephen Hawking made important contributions to the theory of black holes and cosmology.

The Mona Lisa is a famous portrait painted by Leonardo da Vinci, displayed in the Louvre Museum in Paris. The Sistine Chapel ceiling was painted by Michelangelo between 1508 and 1512. Van Gogh painted Starry Night in 1889. Picasso co-founded the Cubist movement in the early twentieth century. Claude Monet was a French Impressionist painter known for water lily series and the painting of his garden in Giverny.

Computers use binary representations of data. A bit is the smallest unit of information, and a byte consists of eight bits. The CPU is the central processing unit of a computer. RAM stands for random access memory. The Internet is a global network of interconnected computer networks. The World Wide Web was invented by Tim Berners-Lee in 1989 at CERN. Email uses protocols such as SMTP, IMAP, and POP3 to send and receive messages.

Programming languages include Python, Rust, JavaScript, Go, C, C++, Java, and many others. Python is known for readable syntax and is widely used in data science. Rust emphasizes memory safety without a garbage collector. JavaScript is the primary language for web browser scripting. Functional programming languages include Haskell and Lisp. Lisp is one of the oldest high-level programming languages, designed in 1958.

Mathematics covers many fields. Algebra deals with symbols and rules for manipulating them. Geometry studies shapes and spaces. Calculus, developed by Newton and Leibniz, deals with continuous change. Statistics analyzes data and uncertainty. Number theory studies the properties of integers. Topology studies properties preserved under continuous deformations. Prime numbers are positive integers greater than 1 with no divisors other than 1 and themselves.

The Pythagorean theorem states that the square of the hypotenuse of a right triangle equals the sum of the squares of the other two sides. Pi is the ratio of a circle's circumference to its diameter, approximately 3.14159. The natural logarithm has base e, where e is approximately 2.71828. The golden ratio, often denoted by the Greek letter phi, is approximately 1.61803.

Languages of the world fall into several major families. The Indo-European family includes English, Spanish, Russian, Hindi, German, and French. The Sino-Tibetan family includes Mandarin, Cantonese, and Tibetan. Arabic is the most widely spoken Semitic language. Swahili is a Bantu language widely spoken across East Africa. Japanese and Korean are language isolates with disputed relations to other families.

The Olympic Games originated in ancient Greece, with the first recorded Olympiad held in 776 BC. The modern Olympic Games began in Athens in 1896. The Summer Olympics include athletics, swimming, gymnastics, and many other sports. The Winter Olympics feature events on snow and ice such as skiing, skating, and ice hockey. The FIFA World Cup is the most-watched soccer tournament, held every four years.

Common foods reflect regional traditions. Pasta is a staple of Italian cuisine. Sushi is a Japanese dish featuring vinegared rice and seafood. Tacos are a Mexican dish typically filled with meat, beans, or vegetables. Curry refers to a variety of dishes from South and Southeast Asia. Bread is a staple in many cultures, with countless regional varieties. Cheese is produced from milk in many forms — soft, hard, aged, fresh, blue. Brie is a soft cheese originally from the Brie region of France. Cheddar is a hard cheese from the English village of Cheddar. Parmesan is a hard Italian cheese aged for at least twelve months. Mozzarella is a fresh Italian cheese traditionally made from buffalo milk.

The human body has eleven major organ systems. The cardiovascular system circulates blood throughout the body. The respiratory system handles breathing and gas exchange. The nervous system processes information and coordinates responses. The musculoskeletal system enables movement. The digestive system breaks down food. The immune system defends against pathogens. The endocrine system regulates hormones. The reproductive system enables procreation. The urinary system filters waste. The integumentary system covers the body. The lymphatic system supports immunity and fluid balance.

Common emotions include happiness, sadness, anger, fear, surprise, and disgust. Empathy is the capacity to understand another person's perspective and feelings. Memory is the brain's capacity to encode, store, and retrieve information. Sleep is essential for cognitive function and physical recovery. Dreams occur primarily during the REM phase of sleep. Learning involves the modification of synaptic connections in the brain.

The economy of a country is shaped by its industries, trade, and policies. GDP measures the total value of goods and services produced. Inflation is the general rise in prices over time. Currency is the medium of exchange used in transactions. Banks accept deposits and provide loans. Stock markets allow companies to raise capital from investors. Bonds are debt instruments issued by governments or corporations. Cryptocurrencies are digital currencies secured by cryptography.

Education systems vary across countries. Primary education typically covers ages five through eleven. Secondary education extends through the teenage years. Tertiary education includes universities and colleges. Many countries offer vocational training as an alternative pathway. Lifelong learning has become more common as careers evolve over time. Online learning platforms have expanded access to courses worldwide.

Climate refers to long-term weather patterns of a region. Tropical climates are warm year-round. Temperate climates have distinct seasons. Polar climates are cold throughout the year. Deserts are arid regions with low precipitation. Rainforests receive abundant precipitation and host high biodiversity. Climate change refers to long-term shifts in global temperatures and weather patterns due to human activity and natural processes.

Animals can be broadly classified as vertebrates and invertebrates. Vertebrates include mammals, birds, reptiles, amphibians, and fish. Invertebrates include insects, arachnids, mollusks, crustaceans, and many other groups. The blue whale is the largest animal alive today. The ostrich is the largest living bird. The cheetah is the fastest land animal, capable of speeds over 70 miles per hour. The peregrine falcon dives at speeds over 200 miles per hour, making it the fastest bird.

Plants perform photosynthesis using chlorophyll, the green pigment in their cells. Roots absorb water and nutrients from the soil. Leaves are the primary site of photosynthesis. Flowers produce seeds for reproduction. Common trees include oak, maple, birch, pine, and palm. The redwood is the tallest tree species. The bristlecone pine is among the longest-lived trees, with some individuals over 4,000 years old.

Famous landmarks span the globe. The Eiffel Tower in Paris was completed in 1889. The Statue of Liberty in New York Harbor was a gift from France. The Great Wall of China stretches thousands of kilometers across northern China. Machu Picchu in Peru is a fifteenth-century Inca citadel. The Taj Mahal in India is a mausoleum built in the seventeenth century. Stonehenge in England is a prehistoric monument made of standing stones. The Pyramids of Giza in Egypt were built around 2500 BC.

Common units of measurement include the meter for length, the kilogram for mass, the second for time, and the kelvin for temperature. The metric system is used worldwide for scientific work and in most countries. The United States primarily uses customary units such as feet, pounds, and Fahrenheit. The pound is approximately 0.45 kilograms. A mile is about 1.6 kilometers. A gallon in the United States is about 3.8 liters.

In music, scales include the major and minor scales as well as modes such as Dorian and Mixolydian. A chord is a group of notes played together. Common chords include major triads and minor triads. Tempo refers to the speed of a piece of music. Rhythm is the pattern of beats and accents. Melody is a sequence of notes that form a recognizable tune. Harmony combines multiple notes to create a pleasing sound.

Religions of the world include Christianity, Islam, Hinduism, Buddhism, Sikhism, Judaism, and many others. The Bible is the sacred text of Christianity. The Quran is the holy book of Islam. The Vedas are foundational texts in Hinduism. The Tipitaka contains key teachings of Buddhism. The Torah is foundational to Judaism. Religion has shaped culture, art, and political life for millennia.

Sports popular worldwide include soccer, basketball, cricket, tennis, baseball, and rugby. Soccer is the most popular sport globally, with the FIFA World Cup as its most watched tournament. Basketball was invented by James Naismith in 1891. Cricket originated in England and is widely played in former British colonies. Tennis is a racket sport played individually or in pairs. Baseball has deep historical roots in the United States, with the World Series as its championship. Marathon races trace their origin to the legendary run from Marathon to Athens in ancient Greece.
