We have seen some of the most impressive hammer prices in the art market in recent weeks. Here are a few key sales.
The BBC explains recent Christie's London sales:
A "blue period" Picasso has fetched £34.7m at auction in London.
Christie's says the event will be the biggest art auction ever held in London. It forms the centrepiece of a week of arts sales in the capital, where a self-portrait by Edouard Manet has already been snapped up for £22m.
Prices have soared recently, with Picasso's 1932 picture Nude, Green Leaves and Bust fetching $106m (£72m) in New York last month, making it the most expensive art work sold at auction.
In The Wall Street Journal's A Flight to Tangibles, world famous art dealer David Nahmad describes the art market. "It is simple," says David Nahmad, one of the world's most famous art dealers. "A lot of investors are distrustful of equities. They are terrified of cash that pays 0% at the bank and is threatened by the 'great inflation' lying one to two years ahead."
He adds, "There is no argument over their worth; they just grow constantly in value in an art market that is awash with money but short of supply. They are also very safe. If the world collapses but you own a Picasso, then amid the ruins you still own a Picasso. What we are seeing is a flight into tangibles. It has happened many times before."