The view you may admire if you look up entering the great hall of the Villa Borghese Pinciana in Rome.  I will not speculate on its size, but the fresco is for sure more than 100 meters big.

Villa Borghese Pinciana is a famous art gallery in Rome. The villa does not look impressive from the outside. But its interiors, besides containing an art collection, are a true masterpiece in themselves with floors, walls, and ceilings richly decorated, among others with colorful frescos. The central hall fresco, as you can see on the close-ups below, is a very detailed one. How great work this is I realized only after I processed the random made photos back home.

Frescoes were a common technique used to decorate ceilings and walls in Rome, in ancient times as well as during the Renaissance. It was adopted in many other places and countries usually in churches, palaces, and villas belonging to the rich. The technique was also applied in China and India. The true fresco technique involves painting with a water-color on the wet plaster. If the painter did not manage to put color onto the plaster before it dried up, the plaster had to be removed and put on once again. Frescoes were also painted with a technique called fresco secco, where the painting was applied on dry plaster. (Secco stands in Italian for dry, fresco – for fresh). The significant difference between a true fresco and the fresco secco is its durability. In the case of a true fresco during the drying process, the color becomes part of the plastered wall, and this way the fresco painting may preserve longer. Authentic frescoes are not suitable as a painting technique for countries where the climate is wet and cold.

More on Galleria Borghese >>>