"Horizontal" is the fourth album by the Bee Gees, and the second to receive an international release. After Bee Gees 1st, the Bee Gees went straight into their next album. Horizontal has a much bigger sound than 1st and, with more use of electric guitars, it has a much harder edge. There is also less reliance on strong melodies and more on abstract lyrics. And, of course, the album features the first ever Bee Gees number one single, the anti-flower-power tour de force 'Massachusetts'.