
The western tunnel was designed by Sir Alexander Binnie and built by S. Pearson & Sons, and work began in 1892. When the tunnel was officially opened by the Prince of Wales in May 1897, it had cost £1.4 million, and seven workmen had died during construction. To clear the site in Greenwich, around 600 houses were demolished, including, legend has it, one which originally belonged to Sir Walter Raleigh.
The second, eastern, tunnel was opened in 1967. It is wider and lacks the sharp turns of the western tunnel, which were reputedly the result of a swerve to avoid a plague burial ground. Its construction involved the building of two distinctive ventilation towers, designed by architect Terry Farrell, which stand in Blackwall. The southern ventilation shafts rise through the Millenium Dome, hence the hole in the roof.
For more on the Blackwall Tunnel, see http://www.blackwalltunnel.com/