Observation tower

An observation tower is a tower built wholly or partly to provide an elevated vantage point from which people can look out over the surrounding landscape or cityscape, usually through an unobstructed 360-degree field of view. Unlike a watchtower, which is occupied for surveillance or fire detection over an extended period, a dedicated observation tower exists principally so that visitors may enjoy or study a panoramic view. Observation towers are typically at least 20 metres (66 ft) tall, so that they clear the surrounding tree canopy or built environment, and have historically been constructed in stone, brick, timber and iron; reinforced concrete, structural steel and glued laminated timber predominate in modern examples. Because a tall structure is expensive to build and maintain for viewing alone, observation functions are very often combined with another use. Many of the world's best-known observation towers are also broadcasting towers, and observation decks are routinely incorporated into water towers, church steeples, lighthouses, high-rise buildings and even the pylons of bridges. Admission fees and tower restaurants help to offset construction and running costs, and in many cities the tower has become a landmark and a symbol of civic identity. Structures closely related to the observation tower include the crow's nest, the belvedere, the viewing platform, the observation deck, the gyro tower and the observation wheel.