Inauspiciously tucked away in one of Vienna's drabber neighborhoods lies a culinary treasure, opened in 1928, in the same family ever since, and well known throughout the country. Guests dine in elegant rooms decorated with French tapestries, or in the beautiful, glass-enclosed winter garden, which overlooks a quiet courtyard. The chef-owner is renowned for his French-based cuisine and light, delicate sauces. The menu changes seasonally and fresh seafood is flown in daily. Look for loup de mer, a mild white fish in saffron sauce, and a side dish of potato mousseline with black truffles and fried parsley. Wine Spectator has proclaimed Altwienerhof's 25,000-bottle wine collection one of the great wine cellars of the world, the only restaurant in Austria to be so honored. Reservations essential. Jacket and tie.