They say the best things in life are free, but try telling that to the art-lover who owns a Leonardo da Vinci or Vincent van Gogh masterpiece. World-renowned auction house Christie's has revealed its top 10 most expensive lots sold in 2017 including da Vinci's 500-year-old mystical masterpiece, Salvator Mundi, which was bought for an eye-watering $450,312,500(£342,182,751). An Andy Warhol painting, two pieces of work by Cy Twombly, Max Beckmann’s Hölle der Vögel and Fernand Léger’s Contraste de Formes all made it into the top 10 list after buyers battled it out in the auction room.