Sunday, September 23, 2012
An observation tower is a structure used to view events from a long distance and to create a full 360 degree range of vision. They are usually at least 20 metres (65.6 ft) tall and made from stone, iron, and wood. The towers first appeared in Germany at the end of the 18th century, and their numbers steadily increased, especially after the invention of the elevator.
1. Euromast, Netherlands
Monday, September 17, 2012
Usually, rock islet is a landform composed of rock, lying offshore, uninhabited, and having at most minimal vegetation. But sometimes, rock islets don't look exactly like this - some are naturally strange looking, and some of them people have adapted to their own needs and made them pretty unusual. Uniqueness makes these small islands very popular among local visitors, foreign tourists and photographers from around the world.
1. New Eddystone Rock, Alaska, USA
|New Eddystone Rock at low tide link|
Monday, September 10, 2012
Star-shaped forts are a particularly interesting type of fortification. They first appeared around the time that gunpowder became commonly used in warfare (first seen in the mid-15th century in Italy). The unusual shape of the forts and the fact that they were made of hard-to-shatter brick (rather than the traditional stone) helped the forts stand up to cannonball fire. These incredible structures are among the most memorable, the most beautiful, and the most historically important forts from around the world.
1. Fort Carré, France
Saturday, September 1, 2012
Navigable aqueducts (sometimes called water bridges) are bridge structures that carry navigable waterway canals over other rivers, valleys, railways or roads. They are primarily distinguished by their size, carrying a larger cross-section of water than most water-supply aqueducts. Although Roman aqueducts were sometimes used for transport, aqueducts were not generally used until the 17th century when the problems of summit level canals had been solved and modern canal systems started to appear.
1. Pontcysyllte Aqueduct, UK