Running up the centre of the tallest free-standing stone column in the world, this 311 step stairway takes the visitor straight to the top of the Monument erected to commemorate the Great Fire of 1666.

The Monument – actually a Doric column – was built close to Pudding Lane in the City – where the fire is believed to have started – between 1671 and 1677. It was designed by Sir Christopher Wren in collaboration with City Surveyor Sir Robert Hooke.

The cantilevered stairway – each step of which measures exactly six inches high – leads up to a viewing platform which provides panoramic views of the City. Above the platform stands is a large sculpture featuring a stone drum topped with a gilt copper urn from which flames emerge as a symbol of the fire (King Charles II apparently squashed the idea of an equestrian statue of himself lest people think he was responsible for the fire).

Interestingly, the circular space in the centre of the stairway was designed for use as a zenith telescope (a telescope which points straight up). There is a small hatch right at the top which can be opened up to reveal the sky beyond and a subterranean lab below (reached through a hatch in the floor of the ticket both) where it was envisaged the scientist could take measurements using a special eyepiece (two lenses would be set into the actual telescope). But it wasn’t successful (reasons for this could have been vibrations caused by passing traffic or the movement of the column in the wind).

Hooke also apparently attempted to use the staircase drop for some other experiences – including measuring differences in air pressure.

Among those who have climbed the stairs was writer James Boswell who visited the Monument and climbed the stairs in 1763. He suffered a panic attack halfway up but was able to complete the climb.

WHERE: The Monument, junction of Fish Street Hill and Monument Street (nearest Tube station is Monument); WHEN: Check website; COST: £5.40 adults/£2.70 children (aged five to 15)/£4.10 seniors (joint tickets with Tower Bridge available); WEBSITE: www.themonument.org.uk