The ultimate Valentine’s day gift: one of the five Hanging Hearts by Jeff Koons, each uniquely coloured. When the red version sold for $23.6 million at Sotheby’s New York in 2007, it set a record at the time for a work by a living artist. Out of budget? Make a trip to Francois Pinault’s Palazzo Grassi, Venice, where the heart beats dramatically overlooking the Grand Canal.