The word "vastness" means a great or immense size or extent. It refers to something that is very large or wide in area, scope, or magnitude. Full definition
The endless repetition of individual elements evoke a sense of vastness of our environment and at the same time generate a state of calmness. (minigalerie.nl)
Enjoy the unmatched thrills of Parasailing and lose yourself in vastness of magnificent turquoise waters. (roamingpirates.com)
She says that blue is associated with vastness; the skies are blue, the oceans are blue.» (theletteredcottage.net)