We get a lot of press releases in the Renovation Contractor inbox, many of them completely irrelevant to us – like the no-expenses paid invitation to attend the grand opening of a beauty salon in London, England. But another one sent from the English capital did catch our attention. It’s from a law firm about a presentation they’re giving called, “Defend yourself from digging neighbours.” The session is in response to the proliferation of so-called “mega basements” in the high-priced city. These are multi-storey below ground excavations to house movie theatres, pools, gyms, and even panic rooms. The firm tallied 112 mega basement projects in London in the past decade, and a further 785 “large basements.” Sounds like a strong underground economy.