premise: Splendid sculpture of the Two Slaves by Michelangelo; Leonardo da Vinci's fabled Mona Lisa (La Joconde), but also his sublime Virgin of the Rocks; Titian's voluptuous Woman at her Toilet; the poignant Old Man and His Grandson by Ghirlandaio.
hypothesis: Out of all the featured works, Mona Lisa is easily the most popular.