A Sacher Torte consists of a layer of apricot marmalade between two layers of chocolate. It is named after the hotel where it was first served, Hotel Sacher in Vienna, Austria where you can still can order one made according to the original recipe.

Each year Hotel Sacher alone uses, one millon eggs, 70 tons of sugar, 60 tons of chocolate, 35 tons of apricot marmalade, 25 tons of butter and 30 tons of flour in the making of Sacher Torten.

If you want to taste one, there is no need to go to Vienna, you can probably buy one at your local café.
If you really feel like trying out the real thing, you can order one over the Internet and they'll send it to you by DHL.