The Prado Museum and Google Earth have partnered to provide a virtual tour of the museum which features 14 of the museum's paintings in ultra high resolution. These images have a resolution of 14,000 megapixels, about 1,400 time the size of a photograph taken with a standard 10-megapixel camera. They were stitched together from more than 8,000 high-resolution images of the paintings. While there is no substitute for seeing the original works, the details that one can observe are incredible. In many cases they are impossible to see in person.
The featured works are Artemis by Rembrandt, Self-portrait by Dürer, The 3rd of May by Goya, The Nobleman with his Hand on his Chest by El Greco, The Cardinal by Raphael, Descent from the Cross by Rogier van der Weyden, The Emperor Carlos V on Horseback by Titian, The Garden of Earthly Delights by Hieronymous Bosch, Jacob’s Dream by Ribera, The Immaculate Conception by Tiepolo, The Annunciation by Fra Angelico, The Crucifixion by Juan de Flandes, Las Meninas by Velázquez, and The Three Graces by Rubens.
To see these photographs, you must have Google Earth installed on your machine (you can download it here). The Google Earth User Guide is a good place to start if you are new to the software. The pictures can be found in the preview section of the geographic web part of the layers menu.