Known to one and all as ‘the ’ (for obvious reasons when you see its incredible shape), 30 St Mary Axe – as it is officially and far more prosaically named – remains London’s most distinctive skyscraper, dominating the city despite actually being slightly smaller than the neighbouring NatWest Tower. The phallic Gherkin’s futuristic, sci-fi exterior has become an emblem of modern London as recognisable as Big Ben or the London Eye.

Built in 2002–03 to a multi-award- winning design by Norman Foster, this is London’s first ecofriendly skyscraper: Foster laid out the offices so they spiral around internal ‘sky gardens’. The windows can be opened and the gardens are used to reprocess stale air, so air-conditioning is kept to a minimum. Its primary fuel source is gas, low-energy lighting is used throughout the building and the design maximises the amount of natural light let into the building, meaning that less electricity is used. You’ll have to take our word for it though, as there’s unfortunately no access to the public.