An observation tower is a structure used to view events from a long distance and to create a full 360 degree range of vision to conduct the long distance observations. They are at least 20 metres tall and made from stone and wood. Many modern towers are used as TV towers, restaurants, or churches; the towers first appeared in Germany at the end of the 18th century, their numbers increased after the invention of the lift. Observation towers that are used as guard posts or observation posts over an extended period to overlook an area are called watchtowers instead. Observation towers are an visible sight on the countryside, as they must rise over trees and other obstacles to ensure clear vision. Older control rooms have been likened to medieval chambers; the heavy use of stone and wood in their construction helps to create this illusion. Modern towers have observation decks or terraces with restaurants or on the roof of mountain stations of an aerial ropeway. Observation towers are used as location of radio services within the UHF/VHF range.
In some cases this usage of the tower is at least as important as its use as an observation tower. Such towers are called TV towers or telecommunication towers. Many towers are equipped with a tower restaurant and allow visitors access via elevators. Common is the usage of water towers as observation towers; as in the case of TV towers the visitor will reach the observation deck by elevator, at a lower height above ground The typical height of the observation deck of water towers is 20 metres up to 50 metres, while the typical height of the platform of TV towers is from 80 metres up to 200 metres. Some church towers may have observation decks, albeit without an elevator. Many other buildings may have towers. In particular prior to World War I rambler associations, some municipalities, built observation towers on numerous summits; these towers were built of stone, however sometimes wood or iron was used. At nearly all these towers access to the observation deck at a height of between 5 and 40 metres, is only possible by way of stairs.
Most of these towers are used only for tourism, however some of these towers might be used, at times of high forest fire risk, as fire observation posts or in times of war as military observation posts with anti-aircraft positions placed beside it. Further uses were not intended at most of these buildings, although some of these towers today now carry antennas for police/fire engine radios, portable radio or low power FM- and TV-transmitters. Older observation towers have a flag pole at its top; some of these towers are permanently accessible, either free or with the payment of an admission fee. Others are accessible only at certain times, in most cases only with the payment of an admission fee. At these towers the platform is open, with some having a restaurant in the basement. There are towers with a much more extensive use; the observation tower on Rossberg mountains in Reutlingen contains a hotel within its structure. Although most of these towers were built before World War I, such structures are still being built, in particular as attractions at horticultural shows.
Modern observation towers are in most cases no longer built of brick, but concrete and wood are used as the preferred building materials. Permanent observation towers are sometimes found in amusement parks, however in parks where each attraction is not separately paid for, panorama rides are preferred. Watch towers are observation towers. Speaking, control towers fall into this category, although surveillance from these structures is done in a non-optical way using Radar. Watch towers have a closed pulpit to protect the observer against bad weather. Watch towers do not have an elevator as a rule, since these buildings are not higher than 20 metres. Active watch towers are not as a rule accessible to the public, since they serve for the monitoring of sensitive ranges; however watch towers can be quite ordered for forest fire monitoring a platform accessible for the public or be used during times without forest fire risk as observation towers. Shut down watch towers can however be converted to observation towers.
Some radio towers were so built that they can be used apart from their function as transmitting tower as observation tower. A condition for this is a sufficiently stable construction, which permits a permanent safe visitor entrance without interruption of the transmission services; this is the case for towers for radio services in the UHF/VHF-range the case, not however for most types of radio towers for long and medium wave, why a use of these structures as observation tower is impossible in most cases. That the use of a tower as radio tower for medium wave and observation tower not well fits, showed up in Radio Tower Berlin, which carried together with an 80 metres high mast a t-antenna for medium wave and stands on insulators; however one notices at the first experimental transmissions that at the tower voltages would arise, which would have unpleasant consequences for visitors and so the tower was grounded by the elevator shaft. However this shifted direction of main beam of transmitter away from actual supply area, the city of Berlin.
As before World War II nearly whole radio traffic took place in the long -, medium and shortwave range, first after World War II with introduction of radio services in UHF/VHF-range required towers only acting as antenna carriers, r