This is a sculpture known as 'The Spheres' or commonly known as 'The Malls Balls'. It's a common meeting spot here in Adelaide, South Australia, found in Rundle Mall.
The #mallsballers hashtag is a reference to both this sculpture and also the term 'ballers' or those who are winning at life (financially, socially, etc).
If you look closely, you can still see scratches where they have removed recent graffiti vandalism.
