The Celestials are a race of beings who stand at 2,000+ft, and exhibit god-like power and abilities.
They take on the appearance of humongous humanoids clad in containment suits/armor, though their true form underneath is not known.
Their origin is shrouded in mystery, but they are known to be one of the oldest and most powerful races in the Marvel Universe. The Celestials spend most of their time creating and evolving life-forms, destroying those they deem unfit. They have made multiple visits to Earth (events known as Hosts) and are the reason that homo sapiens are able to develop superpowers.