What is the greatest mural or fresco ever painted?

Painted straight onto walls and ceilings, so none of them can be moved, sold or rehung. Some are flaking; one was smashed to rubble on purpose.

1

The Last Supper

Leonardo's Milan refectory wall, painted in an experimental dry technique that started failing almost at once.

2

The Sistine Chapel Ceiling

Michelangelo's four-year ceiling, more than 300 figures across 500 square metres.

3

The Creation of Adam

The near-touching hands that became the most quoted image in Western art.

4

The School of Athens

Raphael's Vatican wall gathering every ancient philosopher into one hall.

5

The Last Judgment

Michelangelo's altar wall, painted 25 years after the ceiling and censored within a generation.

6

The Scrovegni Chapel

Giotto's Padua cycle of 1305, where Western painting learns to show human feeling.

7

Detroit Industry Murals

Diego Rivera's 27 panels of the River Rouge plant, painted for the Detroit Institute of Arts.

8

The Allegory of Good and Bad Government

Lorenzetti's 1339 Siena council-room walls, the first great secular fresco cycle.

9

The Ajanta Caves paintings

Buddhist wall paintings cut into Indian rock from the second century BCE onward.

10

Man at the Crossroads

Rivera's Rockefeller Center mural, destroyed in 1934 after he refused to remove Lenin's face.

11

The Triumph of Death

The Palermo fresco of a skeletal horseman that Picasso studied before Guernica.

12

The Cathedral of Florence dome fresco

Vasari and Zuccari's Last Judgment inside Brunelleschi's dome, the largest such surface in the world.