While the world’s leading specialist insurance brokers are inside underwriting everything from astronauts’ lives to Taylor Swift's legs, people outside stop to gawp at this famous 'inside-out' building designed by Richard Rogers, one of the architects of Paris' Pompidou Centre. Completed in 1986, the stainless-steel ducts, vents and staircases are exposed on the outside for all to see. It's not open to the public.