Simplify the following text for a Grade 6 native English-speaking person.
Original: Opened by the South Eastern Railway on 1 September 1866 , the original station building was designed by Sir John Hawkshaw and J.W. Barry and was characterised by its two Wren-style towers , 23 f square and 135 f high , which faced on to the River Thames .
Simplified: The station was opened by the South Eastern Railway on 1 September 1866 . The original station building had two Wren-style towers , 23 f square and 135 f high , which faced on to the River Thames .