It’s all how you look at it.
Here, you see, it is the world.
A three-dimensional optical illusion created by French artist Francois Abelanet was created outside Paris City Hall.
The video’s in French, but language is not an issue. It shows the work needed to make this illusion work.
The world outside a French town hall
"Vous etes ailleurs" ou a l’Hotel de Ville ? by mairiedeparis
– How A Parisian Artist Created This Stunning Optical Illusion, Gizmodo>>
– "Vous etes ailleurs" ou a l’Hotel de Ville ?, Dailmotion>>
– Anamorphosis, Wikipedia>>