Largest in the World

Largest Continent - Asia
Largest Ocean - Pacific Ocean
Largest River - Amazon river
Largest river basin - Amazon river basin
Largest lake (saltwater) - Caspian Sea
Largest lake (freshwater) - Lake Superior
Largest artificial sea - Lake Mead at the Hoover dam, USA
Largest bay - Hudson bay, North Canada
Largest gulf - Gulf of Mexico

Largest george - Grand Canyon, USA
Largest sea - South China Sea
Largest delta - The Sunderbans (India and Bangladesh)
Largest peninsula - Arabia
Largest island - Greenland
Largest country (in area) - Russia
Largest country (in population) - China
Largest temple - Angkor Wat (Cambodia)
Largest archipelago - Indonesia
Largest airport - King Khalid International airport at Riyath (Saudi Arabia)
Largest church - St. Peter's Basilica (Rome)
Largest mosque - Sha Faisal Mosque, Islamabad (Pakistan)
Largest embassy - Russian Embassy (Beijing)
Largest war plane -  Mirage
Largest prison - Khar kov (Russia)
Largest hotel - MGM Grand Hotel and Casino, Las Vegas, USA
Largest Desert - Shahara
Largest forest - Coniferous Forests of Northern Russia
Largest stadium - Strahov (Czech Republic)
Largest library - United States Library of Congress
Largest Museum - American Museum of Natural History (New York)
Largest animal - Blue Whale
Largest land animal - African Bush Elephant
Largest democracy - India
Largest electorate - India
Largest town - Mt. Isa (Queensland)
Largest palace - Imperial Palace (Beijing)
Largest dam - The Three Gorges (China)
Largest landmass - The Eurasian landmass
Largest Park - Wood Buffalo National Park (Canada)
Largest Zoo - Krugal national Park (South Africa)
Largest river island - Majuli, Assan (India)
Largest inland sea - The Mediterranean Sea
Largest canal - Keil Canal (Germany)
Largest reef - The Great Barrier Reef
Largest city (population) - Tokyo (Japan)
Largest estuary - Ob (Russia)
Largest cave - The Mammoth cave, Kentucky (USA)
Largest strait - Tartar strait
Largest wall - The Great Wall (China)
Largest cemetry - Leningrad (Russia)
Largest railway station The Grand Cental Terminal, New York (USA)
Largest university building - University of Riyadh, Riyadh
Largest open university - Indiara Gandhi National Open University, New Delhi (India)
Largest steel plant - Nippon Steel Plant (Japan)
Largest wingspan - Albatross

Largest active volcano - Mauna lao, Hawaii
Largest planet - Jupiter
Largest sea bird - Albatross
Largest diamond - The Cullinan
Largest parliament - The National People's Congress, People's Republic of China
Largest north to south strech - America
Largest cold desert - Gobi desert (Mongolia)
Largest plateau - Pamir (Tibet)
Largest mountain range - The Himalaya
Largest statue - Statue of Liberty (USA)
Largest bank - World Bank (Washington)
Largest army - China
Largest cricket stadium - Melbourne Cricket Ground, Melbourne (USA)
Largest navy - USA
Largest airforce - USA
Largest natural satellite - Ganymede (Jupiter)
Largest port - New Jersey port
Largest book publishing company - Mc Graw Hill (New York)
Largest Dome - Astrodome
Largest Epic - Mahabharat
Largest carnivorous animal - Polar Bear