Obelisk   

Finsbury Circus Garden dates to 1606 and is the oldest public park in London.  When we first published this memorial the profile was unidentified and the purpose of the obelisk was a mystery but we have since met Tony Tugnutt who was the Corporation of London conservation office involved in its installation so we can reveal its story.

Following the King's Cross fire some of the recommended safety improvement measures for the underground concerned the ventilation system. This obelisk disguises one of the ventilation chimneys installed at that time (to an underground gas storage tank). Its classical design and the profile were chosen to honour the architect, George Dance the Younger, who, as the City Surveyor, laid out the Finsbury Estate as a residential suburb, 1775-1800. He was the first to introduce formal, planned crescents and circuses to London.
Finsbury Circus Garden itself dates back to 1606 and is the oldest public park in London. In WW2 it was used as a barrage balloon site.

Another of these post-King's Cross ventilation shafts is on LondonRemembers at Greathead. More monuments hiding vent shafts are the National Police Memorial, the Newgate Street Clock the Battle of Britain memorial, St John the Baptist upon Walbrook, and the column in Paternoster Square is discussed at Temple Bar.  Caroline's Miscellany has found one masquerading as an ornate Victorian lampstand. Londonist points out a similarly OTT one at Tooting Bec.

There are ventilation grills at the Duke of Wellington Statue (venting the underground) and at the Wellington Arch (venting the road tunnel).