MOST people know that the Monument was designed by Sir Christopher Wren as a memorial to the Great Fire of 1666, its 202ft (61m) being the distance from its base to the bakery in Pudding Lane where the fire started. The tallest free-standing stone column in the world, it opened in 1677, taking several years to build because of the amount of stone required – there being a shortage with so much rebuilding after the Great Fire. No new wooden building were allowed in the City of London after the fire.
(The San Jacinto Monument, Texas, opened in 1939 and is 600ft [180m] tall, while the Washington Monument  is 555ft [170m] high – so don’t believe any guide who says the Monument is the highest stone monument in the world; it is the highest stone column.)
The Monument has been repaired every century since, with its latest renovations costing £4.5million and taking 18months. It now includes facilities for firework and laser displays. It re-opened at noon on Monday, February 16, 2009.
What you may not know is that Wren’s collaborator Robert Hooke (1635-1703) originally designed the interior as a giant telescope, with lenses at the top and bottom giving views from a small laboratory at the base. The flaming urn on top has a small trapdoor that opened to allow a view of the sky. (In fact, he – and not Wren – almost certainly designed the whole structure.) Robert Hooke was Surveyor of the City of London after the Great Fire, a founder member of the Royal Society and a noted experimenter. Besides his telescope, he used the Monument’s 311 steps – all exactly six inches high – to measure the effects of different heights on atmospheric pressure. The experiments were soon discontinued because of the constant vibration of traffic.
Hooke was also involved in building the Royal Observatory at Greenwich. He gave his name to Hooke’s Law (the extension of a spring is proportional to the weight hanging from it), built the first reflecting telescope and invented the universal joint (used by him on a telescope to track the sun but now a vital component of motor vehicles and still called a Hooke’s Joint). He also invented the iris diaphragm for cameras, the balance wheel for watches and first used the word ‘cell’ in biology. Quite a man.