Freedom of panorama is an intended limitation of copyright , which enables anyone to reproduce copyrighted works that can be seen from public transport routes without having to ask the author of the work for permission.
"Copyright and Related Rights Act (Copyright Act) Section 59 Works in Public Places
(1) It is permissible to reproduce, distribute and publicly reproduce works that are permanently on public paths, streets or squares by means of painting or graphics, by means of photographs or films. In the case of buildings, these powers only apply to the external view.
(2) The reproductions may not be made on a building. "
(Quoted from: Federal Office of Justice - §59 see: Laws on Internet.de )