Record-Holder Facts You Cannot Afford to Miss
Competition questions regularly target extremes. Know these cold:
- Longest river — The Nile (6,650 km) is traditionally cited as longest; the Amazon (~6,400 km) has the world's greatest discharge volume by a wide margin. Be ready for questions framed either way.
- Highest mountain — Mount Everest at 8,849 meters (2023 survey) above sea level. Mauna Kea in Hawaii is the tallest from base to peak if measured from the ocean floor.
- Largest ocean — Pacific Ocean, covering roughly 165 million km². It is larger than all of Earth's landmass combined.
- Largest desert — Antarctica is the world's largest cold desert (~14.2 million km²). The Sahara (~9 million km²) is the largest hot desert.
- Deepest lake — Lake Baikal in Russia (1,642 m deep), which also holds roughly 20% of the world's unfrozen surface fresh water.
- Largest lake — The Caspian Sea, technically a landlocked saltwater lake, covers 371,000 km².
Major Mountain Ranges
IGB questions frequently ask which country a range is in, which range is the world's longest, or which range separates two regions. The essential ranges to know are the Himalayas (Asia; home to all 14 peaks above 8,000 m), the Andes (South America; world's longest continental mountain range at ~7,000 km), the Alps (Central Europe), the Rockies (North America), the Urals (Russia; traditional boundary between Europe and Asia), the Caucasus (between the Black Sea and Caspian Sea; home to Mount Elbrus, Europe's highest peak at 5,642 m), and the Atlas Mountains (North Africa). Know which major rivers originate in each range.
Major Rivers of the World
Beyond the Nile and Amazon, these rivers appear most often in IGB questions: the Congo (Africa; world's deepest river and second-greatest discharge), the Mississippi-Missouri system (North America; fourth-longest river system in the world), the Yangtze (China; Asia's longest river at ~6,300 km), the Ganges (India; central to South Asian culture and geography), the Niger (West Africa; flows northeast then south in a distinctive arc), the Danube (Europe; flows through 10 countries, more than any other river), and the Volga (Russia; Europe's longest river). For each river, know its source region, the countries it passes through, and where it empties.
Climate Zones and Biomes
The Köppen climate classification divides the world into five main types: tropical (A), dry/arid (B), temperate (C), continental (D), and polar (E). IGB questions may ask which climate type characterizes a region, which biome covers the most land area (boreal forest/taiga), or where specific climate boundaries lie. The world's major biomes — tropical rainforest, savanna, desert, Mediterranean scrubland, temperate grassland, temperate forest, taiga, tundra, and ice cap — each have characteristic locations you should be able to place on a map. The Amazon Basin holds the world's largest tropical rainforest; the Siberian taiga is the world's largest forest biome overall.
Tectonic Features and the Ring of Fire
Physical geography at the IGB level also covers tectonic plates, fault zones, and volcanic features. The Ring of Fire is a roughly horseshoe-shaped zone encircling the Pacific Ocean where approximately 75% of the world's volcanoes and 90% of the world's earthquakes occur. It runs along the western coasts of the Americas, through Alaska and Japan, down through Southeast Asia, and into New Zealand. Key individual features include the San Andreas Fault (California), the East African Rift (a divergent boundary slowly splitting the African continent), and the Mid-Atlantic Ridge (an underwater divergent boundary running the length of the Atlantic). Ocean currents — particularly the Gulf Stream, which moderates Western Europe's climate — also appear regularly in physical geography questions.