Nils Jorgensen/Rex Features
One of the largest collection of toy robots and space toys to be auctioned at Christie's.
Most expensive collection: $7.2 million-plus
Toy collecting has come a long way since the Beanie Baby craze of the '90s, which put an emphasis on "it" playthings of the moment and not on vintage pieces. Donald Kaufman, a retired industry magnate, amassed a collection of 7,000 toys. Unfortunately, he died of a heart attack before he could collect on the sale of those vintage toys. Still, the 79-year-old witnessed the first two auctions of his compilation, which have already garnered more than $7 million. The last three sales of the collection — a set that features century-old toy fire trucks and hand-painted train engines — are set to be carried out next month.