Which bird builds the biggest nest in world?

The bird that builds the biggest nest in the world is the bald eagle. While their nests are not the largest in terms of volume, they are the largest in terms of diameter, reaching up to 10 feet wide and 20 feet deep.

These massive nests are built over many years, with the eagles adding to them each year. The nests provide a safe and secure place for the eagles to lay their eggs and raise their young.