Dozens of prominent Saudi figures are being held at Riyadh's Ritz-Carlton hotel.
Many names are still secret, but the list is said to comprise at least 11 princes. It is part of an anti-corruption drive by the young Crown Prince, Mohammed bin Salman.
The BBC's Lyse Doucet was the first journalist to be allowed inside the hotel. She was given access by Saudi authorities.
(Source: BBC News YouTube channel)