@Route10
I'll add my five:
1. "Mural" 1943, Jackson Pollack
2. "Blue Poles" 1952, Jackson Pollack
3. "Guernica" 1937, Pablo Picasso
4. "Blue Nude" 1907, Pablo Picasso
5. "Dance" 1910, Henri Matisse
Ask me in an hour and that list would be completely different.