The state got the letter back, marked unclaimed, and put the house up at auction.

FORBES: Surprise! We Sold Your House

The base at Neatishead, Norfolk, was put up for auction last week and received one anonymous bid.

BBC: Former RAF Neatishead base relisted on eBay

At the moment, foreign central banks are the star bidders every time these bonds are put up for auction.

ECONOMIST: The unstoppable, surging yen

When sellers put art up for sale at Christie's, they sign a warranty that they have clear title, although the auction house cannot guarantee that this is correct.

ECONOMIST: Art-title insurance