Wallace Line by the Sahul Shelf to New Guinea. The biogeographic boundary known as Lydekker's Line, which separates the eastern edge of Wallacea from the Australian region, has a similar origin to the Wallace line. During ice age glacial advances, when the , both Asia and Australia were united with what are now islands on their respective continental shelves as continuous land masses, but the deep water between those two large continental shelf areas was, for over 50 million years, a barrier that kept the flora and fauna of Australia separated from those of Asia. Wallacea consists of islands that were not
Where Is the Line "assault[s] the listener with a hail of vocal gunfire". Heather Phares of AllMusic commented that the track was one of herBjörk's "tough, no-nonsense songs", and "Rahzel's hard-hitting beats make it starker than anything on "Homogenic"". The music video for "Where Is the Line" was directed by Icelandic artist Gabríela Friðriksdóttir and shot at a stable in Iceland, in November 2004. It was premiered during Friðriksdóttir's exposition at the Venice Biennale in 2005. Originally being one of three films from the artist's "Versations Tetralogia", then edited to fit "Where Is The Line". It shows Björk wearing a dress made of sandbags