To mark the 250th anniversary of the birth of Caspar David Friedrich (1774-1840), Berlin’s Alte Nationalgalerie is presenting a major exhibition on the work of the most important painter of German Romanticism. One of Friedrich’s most famous works, “The Sea of Ice,” painted in 1823-24, was hung in the Alte Nationalgalerie on Monday as part of the exhibition in co-operation with the Kupferstichkabinett Museum of Prints and Drawings of the Staatliche Museen zu Berlin group of museums in the German capital. The loan from the Hamburg’s Kunsthalle is one of the highlights of the exhibition “Caspar D…