One of the most striking and admired structures throughout the history of the City of London is its medieval inhabited stone bridge. Bridges with houses were relatively common in medieval Europe; examples include Bath’s Pulteney Bridge, which is still open for business. However, the old London Bridge, aka the Bridge, as it was commonly known, was the most populous of them all. It is calculated that its 140 houses housed 800 people in the fourteenth century, and the Bridge’s population averaged 500.

The first Harry Potter book was published in 1997 with a hardback print run of just 500, each of which is now worth £40-50,000. Since then the seven Harry Potter books have sold nearly 500 million copies and the eight films based on these books have grossed £6.5 billion, making J K Rowling the world’s richest author with a fortune of around £600 million.