What is the largest animal in the world?
The question of the "largest" animal in the world is subjective and open to interpretation. "Largest" can be measured by length or by weight.

Water: The largest water animal in the World according to the World Wildlife Foundation is the Antarctic blue whale, which can weigh up to 400,000 pounds and stretch to 98 feet in length. For water animals, the Antarctic blue whale is the largest both in terms of length or weight.
Land: The tallest land animal in the world is the giraffe, which can measure between 14-19 feet tall according to National Geographic. The heaviest land animal in the world is the African bush elephant, which can weigh up to 11 tons.

So depending on what you classify as "large" and if you are looking for water animals or land animals, the Antarctic blue whale is the largest water animal, the giraffe is the tallest land animal and the elephant is the heaviest land animal.