The tower above Darwen was built around 1898 for Queen Victoria's diamond jubilee celebrations. It is a major landmark of the area and commands fantastic views of the surrounding area, even as far away as Blackpool. Link
Darwen's Jubilee Tower was more likely to have been built to celebrate Queen Victoria's diamond jubilee (1897) rather than her golden jubilee. A source at http://www.tower-forte.co.uk tells us that it was officially opened in 1898, not 1904.