Complex sentence: The Circle Line was first named as the Marina Line in May 1998, initially planned as a 12-station underground line, starting from Chinatown and Dhoby Ghaut via the National Stadium to either Kallang or Paya Lebar station.
Split into simpler sentences: The Circle Line was first known as the Marina Line in May 1998. The Marina Line was initially planned as a 12-station underground line, starting from Chinatown and Dhoby Ghaut via the National Stadium to either Kallang or Paya Lebar station.