Sideshow Symphonies is an album by the Norwegianavant-garde metal band Arcturus. It was released on September 19, 2005. It is the first to feature Simen "ICS Vortex" Hestnæs as the principal vocalist and Tore Moren as second guitarist, as well as the first Arcturus album released by Season of Mist. It marks yet another change in Arcturus' sound, with a cold, dreamy aesthetic featuring relatively quiet guitars, more prominent vocals, and a slightly reduced use of synthesizers.
A problem during the mastering process occurred which rendered this album to have some audio quality issues such as a noticeable decrease in volume on track #2. The label was rumored to be working on a fix for future pressings of the CD, but this seems to have never been addressed as the audio glitches are still present.
The album artwork features a modification of the artwork found on the Pioneer 10 deep space probe, possibly a reference to the song "Shipwrecked Frontier Pioneer" on the album. The original picture of the naked man is mirrored so that he appears to have three legs and a mask is added, while the image of the naked woman does not appear at all. Also shown is the symbolic representation of the probe's trajectory and a schematic representation of the hyperfine transition of hydrogen.