Freedom of Panorama
The works to which the FOP exception applies vary widely from country to country. The exception generally applies only to works on permanent public display. In some countries, this is only in outdoor public places; in others it extends to indoor places where admission is charged. It may cover only architecture, only architecture and sculpture, or all copyrightable works including literary works.
The article digs into specific copyright law for many countries, including the United States. In the US, buildings completed before 1990-12-01 are in the public domain and may be photographed. Buildings completed after 1990-12-01 are subject to copyright law, with a special exemption for photographs of "permanent" "stationary" buildings: the photographer retains copyright over these photos.
US copyright law extends to artwork, including sculpture permanently installed in public places:
... public artwork installed before 1923 is considered to be public domain, and can be photographed freely. In addition, any public artwork installed before 1978 without a copyright notice is also in the public domain (unless the copyright owner actively prevented anyone from copying or photographing the work until 1978). (Wikimedia)
Photographs of any other artwork are considered derivative works, giving the copyright holder of the work certain rights over the publication of that photograph.