The greatest of the German Romantic painters, Caspar David Friedrich was also one of the most original landscape painters in the history of the genre. He pursued with single-mindedness his personal insight into the spiritual significance of the natural world, often breaking new ground with his choice of subjects. Although he seldom used religious imagery, his landscapes and seascapes unfailingly convey a sense of haunting spirituality. Exquisite examples of Friedrich's delicate and powerful work, "On a Sailing Ship" and "Moon Rising over the Sea" evoke the warmth of human companionship, gently luminous skies, and a silent expanse of sea. The State Hermitage Museum, in the heart of historic St. Petersburg, occupies an ensemble of magnificent buildings on the bank of the River Neva. The grandest of all is the Winter Palace - the former residence of the Russian czars - designed by Francesco Bartolomeo Rastrelli and constructed from 1754 to 1762. Within the walls of this artistic...