3. The National Gallery
Founded in 1824, the National Gallery hosts more than 2,300 Western European paintings and is ranked as the fourth most popular art museum in the world. It exhibits paintings created in 1250 to 1900, including work by Leonardo da Vinci, Rembrandt, and van Gogh. In 1838, a new location was opened in Trafalgar Square in order to move the museum closer to the center of the city and to make the gallery accessible to all. General admission is free, including daily talks on assorted topics and interactive classes for children on Sundays.