It was once the most expensive street in the world, known as "Billionaire's Row" and just a short distance from some of London's most prestigious areas like Hampstead and Highgate. Home to more than 60 enormous mansions, worth a combined hundreds of millions of pounds at the very least, The Bishops Avenue in London has an extraordinary history. But while many of the palatial homes are still lived in, others lie empty and seemingly abandoned, while others have been turned into care homes.

The owners of many of these mansions are a mystery, with ownership in many cases registered to companies based in off-shore tax havens and practically impossible to trace without forensic accountants. However, some owners are known, with the Saudi royal family behind an imposing collection of mansions called "The Towers", which they bought in the 1980s in case Saddam Hussein's Iraq invaded. Another, Heath Hall, was owned by a Czech tycoon and has been rented out by stars including Justin Bieber and Salma Hayek.

Despite their dilapidated state, the houses are still individually worth tens of millions of pounds, and are owned by the sort of unimaginably wealthy people who can just leave such an asset lying unused. Each house is remarkable in its own way. One was once the fortified home of Salman Rushdie, who lived here in secret with 24-hour police protection after the state of Iran put a death warrant on his head.

Another was home to a Nigerian politician — it was seized by squatters after h.