An Aldehyde is an organic compound containing a terminal carbonyl group. This functional group, which consists of a carbon atom which is bonded to a hydrogen atom and double-bonded to an oxygen atom (chemical formula O=CH-), is called the aldehyde group.
Berchtesgaden-a town in Bavaria The town of Berchtesgaden is located near Hitler's Eagle's Nest (Kehlsteinhaus) and can be easily reached by train; there are several hotels and it is an inexpensive place for tourists to stay overnight.
Crow's nest on a tugboat. A crow's nest is a structure in the upper part of the main mast of a ship or a structure that is used as a lookout point. This position ensured the best view for lookouts to spot approaching hazards, other ships, or land. It was the best device for this purpose until the invention of radar.