It is exactly what it sounds like, a freedom. A freedom to be allowed to take photographs in public, such as panorama photos of ones surrounding.
If you want to snap a photo of a building or a nice statue permanently placed in public, you are allowed to do so, and share it however you want. Nobody, such as the architect or artist of said statue, can sue you for intellectual property infringement, nor can they claim copyright of the images which you have taken. Those are yours alone, free to do what you want with.
Some countries, such as the UK and Sweden allow such freedoms, while a few such as Itally disallows it, limiting ones freedoms. Which side of history do you want to be on? The one which forbids photography, or allow it?