The National Gallery in London is home to one of the greatest collections of Western European painting in the world, from the late medieval period to the beginning of the 20th century. Raphael and Titian, Rembrandt and Rubens, Poussin and Claude, Velazquez and Goya, Hogarth and Turner - these are just a few of the great masters whose works are represented in this remarkable institution. Today, the National Gallery is one of the top five tourist attractions in the United Kingdom. Each year, more than four million people explore the gallery's impressive collections, including its renowned holdings in Italian Renaissance art and 17th-century Dutch and Flemish painting. Nicholas Penny has with great difficulty selected 37 paintings from the abundantly rich collection in his care, explaining why he believes them to be especially beautiful or memorable.